fix(agent): verify staged text on a live codex pane and refuse popups

Stage now re-reads the pane after typing (every 50 ms, up to 1 s) and
issues a receipt only for a frame with the same generation, the input
revision its own write moved, and a composer hash equal to the
message's. Codex repaints 30 to 60 ms after the keys, so the first
capture was often stale and stage refused with the text already typed.
Every refusal after typing now says the message may be in the composer
and points at the Ctrl+U recovery. A visible-frame capture reads the
screen and the caret in one tmux invocation, with the old two calls as
the fallback.

Codex draws its suggestion popups above the composer and keeps the
footer, so a staged /stat verified and submit ran /status. Stage now
refuses a leading / or ! and a last word starting with @ or $ before
typing, and stage and submit refuse a frame with popup rows just above
the composer. The pattern and characters are registry data
(composerPopupLine, composerCommandPrefixes, composerCompletionSigils),
read from the codex 0.162.0 bottom_pane sources.

Submit waits until 250 ms after the staged keys: codex turns an Enter
within 120 ms of a typed burst into a newline. POST .../input answers
409 with its seq returned while a guarded submit holds the input lease,
instead of 200 for bytes it never wrote.

Also align the attribution memo comment with the code (a verified file
whose incremental scan fails is not re-walked, since the full walk
reads a superset), and list stage as a fromUser source in CLAUDE.md.

.changeset/bounded-agent-coordination.md

@@ -10,6 +10,8 @@ Codex rollout attribution remembers the attributed file per session and re-verif
 
 The guarded composer read takes its glyph and footer from the CLI registry: codex's `workDetect.promptGlyph` and a new `workDetect.composerFooterLine` capability (config-supplied regex, compiled through the ReDoS guard). Only a CLI declaring it takes guarded input. Codex's footer effort words are now one shared list for this and `modelDetect.screenLine`.
 
+Stage waits for the pane to show what it typed: it re-reads the composer every 50 ms for up to one second and issues a receipt only for a frame showing exactly the message (Codex repaints 30 to 60 ms after the keys, so the first capture was often stale and stage refused with the text already typed). Every refusal after typing now says the message may be in the composer and points at the Ctrl+U recovery. A visible-frame pane capture reads the screen and the caret in one tmux invocation. Stage refuses messages that would change what Enter does (codex: a leading `/` or `!`, or a last word starting with `@` or `$`, which open a command or completion popup) and frames with a suggestion popup above the composer, from three new registry fields (`workDetect.composerPopupLine`, `composerCommandPrefixes`, `composerCompletionSigils`). Submit waits until 250 ms after the staged keys before sending Enter, since codex turns an Enter within 120 ms of typed text into a newline. While a guarded submit is in flight, `POST /api/sessions/:id/input` answers `409 CONFLICT` with its seq returned instead of a `200` for input that was never written.
+
 Document the initial local Codex support and conversation-attribution limits in the API, CLI and packaged skill. Other modes retain labeled snapshots or refuse unverifiable guarded input.
 
 SubmitVerifier Enter re-presses now use the shared input boundary and update `lastSubmitAt` for each retry on every supported CLI. This keeps submission timestamps consistent with delivered Enter attempts while preventing a stale retry from bypassing a guarded submission.