daily-fix: pid file from launch chain child, never pgrep

Overview / Motivation

Auto-filed by /daily 2026-07-22 (transcript sweep). In #1112 (24ae2158, 2026-07-23T05:52–06:30Z), the Monitor TWICE reported the pod dispatcher "exited" while it was alive: the launch chain had populated the pid file from a quick pgrep that captured a TRANSIENT pid. Fixed in-session by writing the python child pid and probing the process PATTERN — but the pid-file contract does not warn against the pgrep-capture shape.

Goal

pod-side-reporting.md item 1 gains the missing clause: the pid file is populated from the LAUNCH EXPRESSION itself ($! of the setsid child / the launcher's echo $$), NEVER from a post-hoc pgrep (which can capture a transient); and liveness monitors probe the process PATTERN (bracketed per the self-match gotcha) as a fallback alongside the pid-file.

Workflow gap

• Bug observed: 2 false "exited" Monitor alarms in one relaunch sequence (24ae2158), each burning a diagnosis round during an already-fragile ZeRO-3 recovery.
• Why it is a workflow gap: item 1 prescribes WRITING the new pid atomically and confirming it, but says nothing about HOW to obtain the pid when relaunching without the launcher — the observed failure used pgrep and captured a transient.
• Confidence: high.
• verified-at-filing: .claude/rules/pod-side-reporting.md item 1 (lines 207–232) read in full at filing: it covers the echo $$ launcher path and the explicit $CHILD_PID atomic rewrite, with NO clause on pid ACQUISITION (pgrep-capture ban) nor the pattern-probe fallback (absence claim, context read), 2026-07-23 UTC.

Proposed change (refine in planning)

Add a sibling clause 1d (or extend 1): pid acquisition comes from the launch expression ($! / launcher $$), never a post-hoc pgrep; monitors probe the bracketed process pattern in addition to the pid-file.

Scope / surfaces

• Primary target: .claude/rules/pod-side-reporting.md (item 1 family).

Constraints / invariants

• The #1597 log-rotation clauses (1b/1c) unchanged. Recursion guard applies.

Provenance

• fingerprint: 200a28402d99

• workflow_fix_target: .claude/rules/pod-side-reporting.md