fix(terminal): address scrolling review and preserve upstream speed policies

Fix transport-timer regression coverage, zero-delta tile handling and capability documentation. Record isolated Codex 0.163.0 transcript and approval evidence; defer event/batch rate and coarse paging policy changes.

Refs: https://github.com/johoja12/Codeman/issues/7

docs/architecture-invariants.md

@@ -225,11 +225,15 @@ Further detail: the `<prefix>: <title>` form (`w3-myapp: fix the login redirect`
 
 ⚠️ **What a mouse-DECSET strip (full or mouse) removes, it must REMEMBER.** Stripping the mouse DECSETs means xterm's `modes.mouseTrackingMode` is permanently `'none'` for those modes, so the browser hand-encodes click reports to compensate (`_sendSyntheticSgrTap`). With no state to consult it did that on EVERY click, which delivered mouse reports to programs that never asked for them: the same pane runs a plain shell whenever the CLI has exited or a `shell` was started inside a claude-mode session, and a shell prints the report as literal text (`[<0;88;20M`), garbling the next line typed. `_recordStrippedMouseMode()` therefore records each stripped sequence as it goes and publishes `cliMouseTracking` through `toState()`, and `_shouldReportMouseToCli()` requires it. ⚠️ Only the TRACKING modes count (1000/1001/1002/1003): 1005/1006 select an ENCODING and 1007 is alt-scroll, and counting those would put the stray reports straight back. ⚠️ The change broadcasts IMMEDIATELY rather than through `broadcastSessionStateDebounced`, because the flag flips when a dialog opens and the user can click that dialog inside the 500ms debounce window. Measured on a live claude 2.x: the CLI holds a tracking mode on continuously in fullscreen (so clicks keep being reported exactly as before; the default inline renderer holds none, measured on 2.1.283 even with `/model` open), while a bash prompt in the same stripped mode reports nothing. Fails toward silence: after a server restart the flag is false until the CLI re-emits, which tmux does at client attach.
 
-**Only claude ≥ 2.1.187 with mouse tracking on forwards the wheel; everything else scrolls local scrollback** (#227 follow-up, `terminal-ui.js:_shouldForwardWheelToApp`). Codex was in the forward list until a reporter hit a completely dead wheel in codex tabs while the scrollbar drag worked. Measured against codex-cli 0.147.0 in a bare tmux: it never enables mouse tracking (`mouse_any_flag=0`) and SGR wheel reports fed to its PTY change nothing on screen, because it runs an INLINE viewport (`alternate_on=0`) and pushes its transcript into the terminal's own scrollback (tmux `history_size` grows) instead of paging in-app. So for codex, local scrollback IS the transcript and forwarding swallowed every tick. Claude repeats this exactly in its default INLINE renderer (measured on 2.1.280: `alternate_on=0`, `mouse_any_flag=0`, `history_size` grows), and swipes on iOS Safari were dead there while codex scrolled; only fullscreen claude (`CLAUDE_CODE_NO_FLICKER=1` or `"tui": "fullscreen"` in `~/.claude/settings.json`: alt screen plus modes 1003/1006) pages its transcript on wheel reports. So claude forwards only while the server-observed `cliMouseTracking` flag is true; a stale-false flag after a server restart falls through to the PageUp/PageDown fallback, never a dead wheel. ⚠️ "The TUI is a strip mode" is NOT evidence that it consumes wheel reports — verify with a real `\x1b[<64;c;rM` write into a live pane before adding a mode here. Hand-encoded SGR TAPS are gated by `_shouldReportMouseToCli()` (the server-observed `cliMouseTracking` flag, recorded by `_recordStrippedMouseMode` in session.ts as it strips, so only ever true for a stripped mode): codex never enables mouse tracking, so since #325 no tap report is sent there at all — click-to-position was already a measured no-op in codex, and a pane that has fallen back to a shell no longer receives `[<0;88;20M` junk.
+**Wheel forwarding requires observed mouse tracking: Claude ≥ 2.1.187 or tracked Codex** (`terminal-ui.js:_shouldForwardWheelToApp`). The original #227 measurement remains valid for **Codex 0.147.0 inline**: `alternate_on=0`, `mouse_any_flag=0`, growing tmux history, and SGR wheel reports do nothing. Claude 2.1.280 inline similarly reports `alternate_on=0`, `mouse_any_flag=0`; forwarding there swallows gestures, so it keeps local scrollback. Fullscreen Claude (`CLAUDE_CODE_NO_FLICKER=1` or `"tui": "fullscreen"`) enables mouse tracking and accepts reports. **Fresh Codex 0.163.0 fullscreen measurement (2026-10-18, isolated local tmux pane)**: `alternate_on=1`, `mouse_any_flag=1`; one `\x1b[<64;10;10M` report moves the transcript one row upward, and `\x1b[<65;10;10M` restores the original screen. This is capability evidence, not a minimum-version promise: untracked Codex (including the maintainer's 0.162.0 measurement with `mouse_any_flag=0`) keeps local history or the hollow-pane paging fallback. Codex does not publish the Claude-only CLI version field, so its gate requires the observed flag rather than a Claude version. The registry records this as `wheelForward.mode: 'mouse-tracking'`; Claude remains `version-gated`. A stale/false flag after startup cannot authorize forwarding. ⚠️ A strip mode alone is not evidence that a CLI consumes SGR reports. Hand-encoded SGR taps remain independently gated by `_shouldReportMouseToCli()`; the older #325 no-op measurement describes untracked inline Codex and must not be generalized to newer tracked fullscreen renderers. Shift/local-history opt-outs and xterm's native mouse/alternate-screen handling remain intact.
+
+Codex 0.163.0 approval check in that isolated read-only/on-request session: the "Would you like to run the following command?" prompt remained on `1. Yes, proceed` after SGR wheel-up and wheel-down over both the transcript and approval option rows 36/37; the requested marker file was not created. The background transcript can scroll while the approval prompt remains fixed. Codex has no Claude hook alert, so a `tabAlerts === 'action'` test cannot detect this prompt and is not a native-wheel safety gate. Native Codex owns its approval selection; do not mistake a hook-only unit fixture for approval-dialog evidence.
+
+Native wheel travel retains upstream pixel/line/page units (100 px = 4 lines; Firefox 3-line events = 3 lines); no one-tick-per-event policy is introduced here. Fractional deltas accumulate within one recent direction, rather than rounding every tiny event up. The first native report of each tab visit bypasses the 40 ms batching timer; later reports coalesce and only unsent bytes can be cancelled on reversal. Every queued batch belongs to its originating session, so switching tabs cannot send its bytes into the newly selected pane. Zero-delta events leave pending movement untouched. Tiles use the same helpers and their own queue/session.
 
 **Wheel/touch forwarding is NOT gated on viewport-at-bottom** (#205, `terminal-ui.js:_shouldForwardWheelToApp`): for sessions verified to scroll their own transcript on SGR wheel reports (claude ≥ 2.1.187 while `cliMouseTracking` is true, i.e. fullscreen; version via the local/docker/remote `--version` probes), the plain wheel AND touch drags forward as coalesced SGR reports (`_forwardScrollToApp` → `_sendSyntheticSgrWheel`, 40ms batches, 5-tick cap, 512-byte queue bound). It used to gate on the viewport being at the bottom so both scrollbacks stayed reachable, but a repaint-mode CLI keeps NO terminal scrollback of its own — xterm's buffer holds only replayed repaint frames, so local scrolling drags the CLI's pinned prompt box up the screen over stale frames; and `scrollToLastNonEmptyLine()` routinely parked the viewport off-bottom, silently pinning the wheel to local. Forwarding now snaps the viewport home first (SGR coordinates address the LIVE screen — a report computed from a scrolled-up viewport would hit-test the wrong row). Local scrollback remains on Shift+wheel and the `terminalWheelLocalScrollback` opt-out (both also cover touch via the shared gate; touch has no Shift, so the setting is its only local pin). `_wheelScrollLines()` normalizes `deltaMode` (Firefox fires LINE deltas ≈3/notch — read as pixels that rounded to 0 and fell to the ±1 fallback, ~4× too slow; PAGE deltas scale by `terminal.rows`) while keeping the #154 Shift-axis trap (macOS trackpads put Shift+scroll magnitude on deltaX). Tests: `test/terminal-touch-tap.test.ts`.
 
-**A false gate on a hollow pane must not mean a DEAD gesture** (#205 round 2, `_maybePageCliTranscript`): every way `_shouldForwardWheelToApp()` returns false leaves a repaint-mode pane scrolling a buffer that has nothing in it (`baseY === 0`) — the version probe came back empty, the CLI really is older than 2.1.187, the `cliMouseTracking` flag is unset (inline claude, or fullscreen right after a server restart), or the user turned on `terminalWheelLocalScrollback`. **opencode is the fifth case, and the gate is false there by design**: its TUI runs on the ALTERNATE SCREEN (1.18.31 measured: tmux `alternate_on=1`, `history_size=0`), so the buffer is hollow, and it IGNORES SGR wheel reports entirely (six `\x1b[<64;…M` reports against an idle pane left the capture byte-identical) while still paging its transcript on PageUp/PageDown (`messages_page_up/down`) — so paging is the only gesture that can reach it, and without it the wheel was silently dead in every opencode tab. The 1.12.0 retest reported exactly that shape for Claude: a wheel that did nothing at all while Fn+Up (PageUp) paged back through intact text, which is the proof that the CLI's own history and the PTY input path were both fine. So under the guard (`_localScrollbackIsHollow()`: the `transcriptPageKeys` capability, gate false, `baseY === 0`) wheel and touch travel is translated into coalesced `\x1b[5~` / `\x1b[6~` through the same 40ms queue as the SGR reports, at half a screen of travel per page key (the key jumps a whole screen; a 1:1 mapping was unusably slow with a discrete wheel). ⚠️ The first event of a trackpad-sized gesture (opening under 2 rows) pages AT ONCE and the travel it skipped is owed back by the rest of the gesture (one page per half screen still). Waiting for half a screen first meant an ordinary trackpad flick (well under 19 rows on a 38-row pane) sent nothing at all. A larger opening event is a mouse-wheel notch (100 px is 4 rows) and accumulates as before, or slow notches, each its own gesture past the gap, would page a full screen apiece. ⚠️ What starts a NEW gesture (and so may pre-pay) is narrow, because every boundary is another free page: (1) a TOUCH CONTACT is one gesture, never split by time: the touch paths tag every call, touchmove and momentum frames alike, with `touchId` (one per touchstart), and a different id (or a wheel event after a touch) is a boundary. touchmove only calls once per whole cell of finger travel, so a slow drag arrives as single lines further apart than any gap; on the gap alone 12 lines at 170 ms each sent 12 PageUps (measured through the real listeners, `test/terminal-touch-paging.browser.test.ts`). (2) Outside a contact, 150 ms of quiet (`PAGE_KEY_GESTURE_GAP_MS`), stretched to one second (`PAGE_KEY_DEBT_MS`) while a pre-paid page is still owed in the SAME direction, so slow small wheel ticks (40 px every 250 ms, a Firefox 1-line notch) pay the debt back instead of each pre-paying a page; after a second of quiet the debt lapses and the next small tick pages at once again. The debt also ends the moment travel repays it (reaches or crosses zero): the rest is plain travel and the 150 ms gap applies again. (3) A direction change inside a gesture (within the gap, or within one contact) drops a pre-paid debt (it belongs to the other direction) and accumulates WITHOUT pre-paying, so a +/-3 px trackpad wobble pages once for its opening event and then nothing; a reversal after the gap is a new gesture and pages at once. A tab switch also starts a new gesture. ⚠️ These gesture rules (first-event page, contact and debt lifetimes, reversal handling, notch accumulation, pinch and sideways-swipe consume) are ONE pure helper, `CodemanTerminalInput.pageKeysForGesture(state, ev, lines, rows, now)`, which both panes call with their own state; never re-derive them in a pane. ⚠️ Three gestures are consumed WITHOUT paging: a pinch (`ctrlKey`, Chrome's trackpad-pinch wheel events), a mostly horizontal swipe (both deltas present and `|deltaX| > |deltaY|`; the touch path locks its own axis first), and anything while the pane's OWN session has the alert `'action'` (a pending `permission_prompt` or `elicitation_dialog`, `updateTabAlertFromHooks` in app.js), so a page key never lands in an open dialog's selector; the primary pane logs that case as `page-keys-dialog-open` so a wheel dead under a stale alert leaves a `[scroll]` line. The dialog check is the one rule outside the helper, because it is per pane: the primary pane reads `tabAlerts` for `activeSessionId`, a tile for its own `sessionId` (usually not the active one). ⚠️ Which modes page is the registry's `capabilities.transcriptPageKeys`, published as `window.__codemanTranscriptPageKeys`, never an id check in terminal-ui.js. Today that is claude, codex and opencode. Codex is on it although it is never forwarded the wheel: newer codex draws on tmux's alternate screen, which the full strip hides from xterm, so its pane is hollow too, Line truncated
+**A false gate on a hollow pane must not mean a DEAD gesture** (#205 round 2, `_maybePageCliTranscript`): every way `_shouldForwardWheelToApp()` returns false leaves a repaint-mode pane scrolling a buffer that has nothing in it (`baseY === 0`) — the version probe came back empty, the CLI really is older than 2.1.187, the `cliMouseTracking` flag is unset (inline claude, or fullscreen right after a server restart), or the user turned on `terminalWheelLocalScrollback`. **opencode is the fifth case, and the gate is false there by design**: its TUI runs on the ALTERNATE SCREEN (1.18.31 measured: tmux `alternate_on=1`, `history_size=0`), so the buffer is hollow, and it IGNORES SGR wheel reports entirely (six `\x1b[<64;…M` reports against an idle pane left the capture byte-identical) while still paging its transcript on PageUp/PageDown (`messages_page_up/down`) — so paging is the only gesture that can reach it, and without it the wheel was silently dead in every opencode tab. The 1.12.0 retest reported exactly that shape for Claude: a wheel that did nothing at all while Fn+Up (PageUp) paged back through intact text, which is the proof that the CLI's own history and the PTY input path were both fine. So under the guard (`_localScrollbackIsHollow()`: the `transcriptPageKeys` capability, gate false, `baseY === 0`) wheel and touch travel is translated into coalesced `\x1b[5~` / `\x1b[6~` through the same 40ms queue as the SGR reports, at half a screen of travel per page key (the key jumps a whole screen; a 1:1 mapping was unusably slow with a discrete wheel). ⚠️ The first event of a trackpad-sized gesture (opening under 2 rows) pages AT ONCE and the travel it skipped is owed back by the rest of the gesture (one page per half screen still). Waiting for half a screen first meant an ordinary trackpad flick (well under 19 rows on a 38-row pane) sent nothing at all. A larger opening event is a mouse-wheel notch (100 px is 4 rows) and accumulates as before, or slow notches, each its own gesture past the gap, would page a full screen apiece. ⚠️ What starts a NEW gesture (and so may pre-pay) is narrow, because every boundary is another free page: (1) a TOUCH CONTACT is one gesture, never split by time: the touch paths tag every call, touchmove and momentum frames alike, with `touchId` (one per touchstart), and a different id (or a wheel event after a touch) is a boundary. touchmove only calls once per whole cell of finger travel, so a slow drag arrives as single lines further apart than any gap; on the gap alone 12 lines at 170 ms each sent 12 PageUps (measured through the real listeners, `test/terminal-touch-paging.browser.test.ts`). (2) Outside a contact, 150 ms of quiet (`PAGE_KEY_GESTURE_GAP_MS`), stretched to one second (`PAGE_KEY_DEBT_MS`) while a pre-paid page is still owed in the SAME direction, so slow small wheel ticks (40 px every 250 ms, a Firefox 1-line notch) pay the debt back instead of each pre-paying a page; after a second of quiet the debt lapses and the next small tick pages at once again. The debt also ends the moment travel repays it (reaches or crosses zero): the rest is plain travel and the 150 ms gap applies again. (3) A direction change inside a gesture (within the gap, or within one contact) drops a pre-paid debt (it belongs to the other direction) and accumulates WITHOUT pre-paying, so a +/-3 px trackpad wobble pages once for its opening event and then nothing; a reversal after the gap is a new gesture and pages at once. A tab switch also starts a new gesture. ⚠️ These gesture rules (first-event page, contact and debt lifetimes, reversal handling, notch accumulation, pinch and sideways-swipe consume) are ONE pure helper, `CodemanTerminalInput.pageKeysForGesture(state, ev, lines, rows, now)`, which both panes call with their own state; never re-derive them in a pane. ⚠️ Three gestures are consumed WITHOUT paging: a pinch (`ctrlKey`, Chrome's trackpad-pinch wheel events), a mostly horizontal swipe (both deltas present and `|deltaX| > |deltaY|`; the touch path locks its own axis first), and anything while the pane's OWN session has the alert `'action'` (a pending `permission_prompt` or `elicitation_dialog`, `updateTabAlertFromHooks` in app.js), so a page key never lands in an open dialog's selector; the primary pane logs that case as `page-keys-dialog-open` so a wheel dead under a stale alert leaves a `[scroll]` line. The dialog check is the one rule outside the helper, because it is per pane: the primary pane reads `tabAlerts` for `activeSessionId`, a tile for its own `sessionId` (usually not the active one). ⚠️ Which modes page is the registry's `capabilities.transcriptPageKeys`, published as `window.__codemanTranscriptPageKeys`, never an id check in terminal-ui.js. Today that is claude, codex and opencode. Codex retains this fallback when mouse tracking has not been observed: alternate-screen drawing is stripped from xterm and can leave a hollow pane, while PageUp still paLine truncated
 
 **Why the wheel went where it went is LOGGED** (`_logScrollRouting`): one console line per session per distinct decision — `[scroll] <id> → forward-sgr|page-keys|local-scrollback|repull-refused-downgrade (mode=…, cliVersion=…, localScrollbackOptOut=…, mouseTracking=…, localScrollbackRows=…)`. #205 ran two rounds of remote guesswork over questions this line answers directly; keep it when touching the routing.