fix(watching): close the review findings on the label and its window

A dual review (Codex CLI and Claude's code-reviewer, same diff, same brief)
found the trust boundary weaker than the comments around it claimed. Eleven
findings, all applied.

The two blockers were both about who can write the row the label is read from.
Claude's window covered two rows, and the second one is the status line, whose
command a session running with permissions bypassed can write into its own
`.claude/settings.json` — so an agent could print `· 1 monitor ·` onto a row of
its own and silence its own idle alert. The default window is one row now, which
is the footer and nothing else, and the constant says why. Separately, the label
reached `data-tab-meta-sig` unescaped while the row is installed with innerHTML,
which is an injection sink for any config-supplied pattern whose capture group is
permissive; it goes through escapeHtml() like every other untrusted string in
that file.

The Codex entry could not be fixed the same way, and now says so. Its row is
third from the bottom only while a terminal runs; with none running that slot
holds the last row of the transcript, so matching the complete row (with the
`/stop to close` tail, window narrowed to three) raises the bar without closing
it. What contains it is `hooks: 'none'`: no hook event from a codex session
reaches notePrompt(), so a forged label costs a wrong badge and cannot quiet an
alert. The registry comment, `docs/cli-registry.md` and the test all state that
rather than claiming a guarantee the code does not have.

Also from the review: the TUI header badge no longer counts an acknowledged
item, which was the same gate the classifier fix already went through and was
wrong for human acknowledgement too; the TUI approval card reads the quiet
reason and drops to a new `info` tone instead of asking for a reply; the badge
carries an aria-label, because the phone it was built for has no hover target;
the schema refuses `watchingLines` without a `watchingLine`; and the pattern and
its window are resolved together rather than one memoized and one not.

Documentation moved with it. The mechanism now lives in
`docs/architecture-invariants.md` with CLAUDE.md keeping the rule and a pointer,
`docs/wiki/Notifications-And-Approvals.md` tells users why a session stopped
buzzing, and both that page and the changeset name the limitation neither did
before: a question asked in plain prose is not a dialog, so it is silenced along
with the false alarms while background work runs.

Verified live again after the narrowing, on an isolated beta: a Claude session
reported `1 monitor` and took its idle prompt acknowledged, and a Codex session
reported `1 background terminal` against the full-row anchor.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/session.ts

@@ -82,6 +82,7 @@ import {
   isSustainedActivity,
   isPaneQuiet,
   watchingLabel,
+  WATCHING_TAIL_LINES,
   IDLE_RECHECK_MS,
   PANE_PROBE_MIN_INTERVAL_MS,
   PANE_PROBE_RECHECK_MS,
@@ -517,6 +518,8 @@ export class Session extends EventEmitter {
   private _workingLineRe: RegExp | undefined = undefined;
   /** Lazily compiled `capabilities.workDetect.watchingLine`. See _watchingLinePattern(). */
   private _watchingLineRe: RegExp | null | undefined = undefined;
+  /** Resolved with the pattern above: how many rows at the foot of the screen to search. */
+  private _watchingWindow = WATCHING_TAIL_LINES;
   private _trustDialogAccepted: boolean = false; // Stops the trust-dialog scan (answered, or given up)
   private _trustDialogAttempts = 0; // Keystrokes sent at the trust dialog
   private _lastTrustDialogScanAt = 0; // Throttle for the trust-dialog screen read
@@ -2760,9 +2763,7 @@ export class Session extends EventEmitter {
     // Called only from the probe, and only with what a capture returned: `null` is
     // "the screen could not be read", which is not evidence that nothing is running.
     if (!pattern || paneText === null) return;
-    // How far up the screen this CLI's row can sit is its own business: Claude writes on
-    // the last row, Codex pins one above its composer. Both stay at the foot.
-    this._watching = watchingLabel(paneText, pattern, getCli(this.mode)?.capabilities.workDetect?.watchingLines);
+    this._watching = watchingLabel(paneText, pattern, this._watchingWindow);
   }
 
   /**
@@ -2773,8 +2774,13 @@ export class Session extends EventEmitter {
    */
   private _watchingLinePattern(): RegExp | null {
     if (this._watchingLineRe === undefined) {
-      const src = getCli(this.mode)?.capabilities.workDetect?.watchingLine;
-      this._watchingLineRe = src ? compileVersionRegex(src) : null;
+      // The pattern and the window it runs over are one decision, so they are resolved
+      // together: how far up the screen a CLI's row can sit is as much a property of its
+      // layout as the row itself. Claude writes on the last row and keeps the default,
+      // Codex pins one above its composer and declares more.
+      const detect = getCli(this.mode)?.capabilities.workDetect;
+      this._watchingLineRe = detect?.watchingLine ? compileVersionRegex(detect.watchingLine) : null;
+      this._watchingWindow = detect?.watchingLines ?? WATCHING_TAIL_LINES;
     }
     return this._watchingLineRe;
   }