sage: brief for the stopRun deadline row (mos-1269), the 191 follow-up row 194 b15's gate found

docs/plans/2026-10-22_stoprun-deadline.md

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+# stopRun reads a live run's status at the deadline (191 follow-up, MVP)
+
+Sage, 2026-10-22, for mos-1269. Row 194 b15's gate found it (honker-0121, sage-2510).
+
+## Why
+
+`stopRun` in packages/processing-control/src/runtimes.mjs (row 191, 4bdc7e0e8) waits in
+`while (now() <= deadline)` (:333). Its final status read is inside `if (now() >= deadline)` (:356-359),
+and the loop sleeps `Math.min(20, Math.max(1, deadline - now()))` (:361). A real sleep can wake past the
+deadline. When it does, the loop condition fails before the final read runs, and :363 returns `'unknown'`
+for a process that is still alive and ignoring SIGTERM and SIGKILL. The expected outcome is `'alive'`.
+
+Row 194's T9a (cli lifecycle.test.mjs:562) caught it in the loaded cli suite: 'unknown' where 'alive' was
+expected, while the same file passed alone. Row 191's tests missed it because their fake clock advances by
+exactly the sleep, so it never overshoots. Live is 86f95bb27, which doesn't carry 191, so nothing running
+is affected.
+
+## Brief: stopRun's deadline branch is the only time exit
+
+No `--after`. 191 has landed. This row lands before row 194 b16, which rebases onto it (mos-1269 item 4).
+
+What to build:
+
+1. The time loop's only exit on time is the existing deadline branch, so the final status read always runs
+   once the deadline passes. One shape is `for (;;)` with the `now() >= deadline` branch as the time exit.
+   The builder picks the shape and records it in BUILD.md.
+2. The other exits stay as they are: record gone (the catch), identity changed, ended or not alive, and the
+   deadline branch's own mapping of `alive`, `killed`, `stopped`, `identity-changed` and `unknown`.
+3. Nothing else in runtimes.mjs changes. Vikunja 502's four items stay out (mos-1269 item 3). They follow
+   row 194.
+
+Tests:
+
+- A fake sleep advances the clock past the deadline while the process stays alive and ignores both
+  signals. stopRun reports `'alive'`.
+- The existing stop-run tests pass unchanged.
+
+Mutants, each killed by a named test:
+
+- M1. The old loop condition `while (now() <= deadline)` with the fall-through `return finish('unknown')`.
+
+Gate: Dewey approves the manifest. The processing-control package's tests (runtimes.test.mjs and
+stop-run.test.mjs among them) and every other touched test file run whole, the business and cli suites are
+green on Sage's gate, and M1 is killed. Row 194 b16's full gate then runs on top of this row. Any red goes to
+Mos (mos-1269).