release: v0.30.4 — supervisor stale-ctx hardening + docs sweeps

[HenryLach]

Patch release wrapping one high-severity bug fix and two coordinated documentation sweeps since v0.30.3.

Patch justification (semver)

• Fixed: real bug fix (process-crashing supervisor stale-ctx), no breaking changes.
• Docs: repo URL and stale package-scope reference sweeps — non-code.

No public API or behavior changes beyond the bug remediation. Patch bump (0.30.3 → 0.30.4) is the appropriate semver level.

Issues / PRs included

#	Title	Severity
#597	Supervisor heartbeat timer crashes pi with stale extension ctx	High — process-fatal during normal batch startup
#604	Pi GitHub URL sweep (badlogic → earendil-works) + install tutorial PATH co-location	Docs
#605	@mariozechner/* stale-references follow-up sweep	Docs

Highlights

• Supervisor heartbeat timer crashes pi with stale extension ctx (uncaughtException in startHeartbeat sendMessage) #597 was the headline fix. External reporter (@beettlle) provided an excellent root-cause analysis with stack trace and proposed three-part remediation. The implementation followed their fix sketch and went through Sage code review, which caught a blocking gap in the initial PR (an indirect call chain via presentBatchSummary that was missed). Final PR addresses both the direct timer call sites AND the indirect path, with 9 regression tests including a mutation-verified behavioral test.
• The two docs sweeps clean up post-rename hygiene from Pi's repo and package-scope migrations earlier in the project's history.

Validation

Run on the merge commit (54ddf91a):

Gate	Result
npm run typecheck	✅ pass
npm run lint	✅ 286 warnings / 671 infos — identical to v0.30.3
npm run format:check	✅ pass
cd extensions && npm run test:fast	✅ 3,723 / 3,724 pass, 1 skipped
node bin/taskplane.mjs help	✅ pass
node bin/taskplane.mjs doctor	✅ pass
npm pack --dry-run	✅ 77 files

After merge

Per the release workflow, I'll push the v0.30.4 tag from local after this PR merges. The .github/workflows/release.yml workflow handles tag validation, test re-run, npm publish --provenance via Trusted Publishing, and the GitHub release with notes extracted from CHANGELOG.

Expected total time after tag push: ~30–60 seconds.