docs: remove/contextualize references to external palace-daemon project

[mvalentsev]

Summary

A few files reference palace-daemon -- an external project not shipped with mempalace. The references landed via PRs #1000, #1201, and #1494. They're not wrong per se, but they're confusing for anyone reading the code or docs without prior context: there's no explanation of what palace-daemon is, and some references cite functions/scripts that don't exist in this repo.

What's referenced

mempalace/backends/chroma.py:1319-1321 (PR #1000)

Comment describes palace-daemon's _auto_repair as a fallback path for runtime HNSW drift. _auto_repair doesn't exist in this codebase (0 grep hits) -- the described fallback is not available to mempalace users.

Already removed in #1602 (pending merge).

mempalace/palace_graph.py:130 and tests/test_palace_graph.py:62 (PR #1201)

Comment and docstring cite palace-daemon's verify-routes.sh smoke test as bug discovery provenance. verify-routes.sh doesn't exist in this repo.

docs/recovery/index-metadata-recovery.md lines 43, 50-51, 140, 194-197 (PR #1494)

The recovery runbook treats palace-daemon as a standard deployment option (sudo systemctl stop palace-daemon.service) and links to files in the external repo under "Related". A reader following this doc has no way to know what palace-daemon is or where to find it.

Suggested fix

• chroma.py: covered by fix(backends): re-arm HNSW quarantine gate on mtime change and explicit reconnect (#1573) #1602
• palace_graph.py / test_palace_graph.py: replace provenance comments with something self-contained (describe the bug, not the external tool that found it)
• Recovery doc: either briefly explain what palace-daemon is in the "Related" section, or drop the palace-daemon-specific systemctl commands and cross-links

@jphein @igorls