test(terminal): restore reversal assertion and clarify scrolling guidance (#7)

docs/architecture-invariants.md

@@ -225,7 +225,7 @@ 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.
 
-**Wheel forwarding requires observed mouse tracking: Claude ≥ 2.1.187, tracked Codex or tracked Copilot** (`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: 'always'` (observed mouse tracking is still required); 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.
+**Wheel forwarding requires observed mouse tracking: Claude ≥ 2.1.187, tracked Codex or tracked Copilot** (`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: 'always'` (observed mouse tracking is still required); 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. Verify with a real `\\x1b[<64;c;rM` write into a live pane before adding a mode here. 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.
 
 **Copilot also receives forwarded reports** (1.0.95 measured in tmux: alt screen, `mouse_any_flag=1`): its mouse DECSETs are stripped so a drag selects, which also stops xterm encoding the wheel for it, so `_shouldForwardWheelToApp` sends the same SGR reports by hand while `cliMouseTracking` is true; six `\x1b[<64;…M` reports moved its transcript 18 lines, a phone swipe takes the same gate, and there is NO version gate.