docs: reconcile CHANGELOG — 2026-W18

[the-care-taker]

Documentation reconciliation

This PR updates CHANGELOG.md to capture the following merged pull requests:

• fix(maintainer): drop pip cache from setup-python #65: fix(maintainer): drop pip cache from setup-python
• chore(caretaker): upgrade pin v0.19.6 → v0.25.0 + thin workflow template #64: chore(caretaker): upgrade pin v0.19.6 → v0.25.0 + thin workflow template
• fix(caretaker): adopt v0.20.0 fleet workflow (OAuth2 envs) #60: fix(caretaker): adopt v0.20.0 fleet workflow (OAuth2 envs)
• chore: upgrade caretaker v0.19.4 → v0.19.6 #59: chore: upgrade caretaker v0.19.4 → v0.19.6
• feat(fleet): add CARETAKER_FLEET_SECRET for signed heartbeats #57: feat(fleet): add CARETAKER_FLEET_SECRET for signed heartbeats
• chore(caretaker): enable fleet-registry heartbeat with OAuth2 #46: chore(caretaker): enable fleet-registry heartbeat with OAuth2

Proposed changelog entry

## [2026-W18] — 2026-04-28

- enable fleet-registry heartbeat with OAuth2 (#46)
- add CARETAKER_FLEET_SECRET for signed heartbeats (#57)
- upgrade caretaker v0.19.4 → v0.19.6 (#59)
- adopt v0.20.0 fleet workflow (OAuth2 envs) (#60)
- upgrade pin v0.19.6 → v0.25.0 + thin workflow template (#64)
- drop pip cache from setup-python (#65)

---

[the-care-taker]

@copilot Please review this generated documentation update for accuracy,
expand any cryptic titles if needed, and merge when ready.

[the-care-taker]

⚠️ Caretaker Escalation

This PR requires human attention.

Reason: Open >24h with no human approval — needs review

The automated system has exhausted its ability to resolve this. Please review and take appropriate action.

Escalation debug dump

Generated at: 2026-05-01T07:26:15.506921+00:00

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