#493 (sqlite): route _initialize() through the _connect() contextmanager
(the one remaining raw sqlite3.connect FD leak); document the auto-commit
contract so the redundant explicit commits are understood.

#529 (book):
- _strip_thinking_preamble: guard `{ not in text` before rindex() so plain
  prose (refusals/errors) no longer raises ValueError -> ERROR block;
  hoist json import to module top.
- llm_json: honor caller max_tokens as max(max_tokens, 2600) instead of
  discarding it; bump default to 2600; fix stale 'minimal' docstring -> 'low'.
- engine.compile_page: rebuild OVERVIEW pages deterministically via
  _materialize_overview_page on force, instead of running the generic LLM
  compiler over hand-built intro/concept-graph/index blocks.
- kb_health.scan_log_health: key repeated-failure detection on the op, not
  the free-text message, removing false positives/negatives + dead block_error.
- services/__init__: drop orphaned notebook_manager lazy-import + __all__ entry.
- PageReader.tsx: restore t() i18n on regenerate buttons; add 'Regenerating…'.
- remove PATCHES.md (developer-local scratch notes).

#484 (zulip): also match the disambiguated @**Name|user_id** mention form;
make the docstring truthful; add coverage.

#500: remove stray PR_DESCRIPTION.md committed to repo root.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

Wrap _connect() in a contextmanager that closes the connection after use,
preventing one leaked file descriptor per query.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

…#529/HKUDS#484

HKUDS#493 (sqlite): route _initialize() through the _connect() contextmanager
(the one remaining raw sqlite3.connect FD leak); document the auto-commit
contract so the redundant explicit commits are understood.

HKUDS#529 (book):
- _strip_thinking_preamble: guard `{ not in text` before rindex() so plain
  prose (refusals/errors) no longer raises ValueError -> ERROR block;
  hoist json import to module top.
- llm_json: honor caller max_tokens as max(max_tokens, 2600) instead of
  discarding it; bump default to 2600; fix stale 'minimal' docstring -> 'low'.
- engine.compile_page: rebuild OVERVIEW pages deterministically via
  _materialize_overview_page on force, instead of running the generic LLM
  compiler over hand-built intro/concept-graph/index blocks.
- kb_health.scan_log_health: key repeated-failure detection on the op, not
  the free-text message, removing false positives/negatives + dead block_error.
- services/__init__: drop orphaned notebook_manager lazy-import + __all__ entry.
- PageReader.tsx: restore t() i18n on regenerate buttons; add 'Regenerating…'.
- remove PATCHES.md (developer-local scratch notes).

HKUDS#484 (zulip): also match the disambiguated @**Name|user_id** mention form;
make the docstring truthful; add coverage.

HKUDS#500: remove stray PR_DESCRIPTION.md committed to repo root.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>