Move Compact Chat to Global Settings

[RANGROO]

Summary

• Move Compact Chat from the retired chat/profile toggle into shared Global Settings.
• Show Compact Chat under Prompt & Rechat in both the PHP and Prisma settings surfaces.
• Enable it by default while continuing to exclude the Narrator from history compaction.
• Preserve an existing chim_context_mode choice during migration, then remove the legacy row and Focus Mode runtime path.
• Publish compact_chat through the status APIs expected by the CHIM client already merged in Dwemer-Dynamics/CHIM#173.
• Update the Local LLM Quickstart path to enable the new global setting instead of recreating the retired option.

Recovery context

PR #739 was mistakenly stacked on #733 and therefore merged into that feature branch rather than unstable. This recovery branch starts directly from current origin/unstable and contains only the Compact Chat feature. After this lands, #733 should be rebased without reintroducing its duplicate Compact Chat changes.

Migration and compatibility

Migration general_settings 20260825001 is idempotent:

• Keep an existing COMPACT_CHAT_ENABLED value when present.
• Otherwise import the legacy public.conf_opts.chim_context_mode value.
• Otherwise use the schema default of true.
• Delete the legacy row only after the global setting is written successfully.

Validation

• PHP lint passed for all 24 changed PHP files.
• JSON schema parse passed: global boolean, default true.
• Focused PHPUnit passed: 8 tests, 14 assertions.
• Catalog, Quickstart, migration-version, and CHIM unstable protocol contract probes passed.
• Full PHPUnit comparison:
  • Feature: 271 tests, 2627 assertions, 16 errors, 2 failures, 1 warning.
  • Exact unstable base: 270 tests, 2625 assertions, the same 16 errors, 2 failures, and 1 warning.
  • The shared failures are existing Windows database/PGPASSWORD, missing ZipArchive, and order-dependent baseline failures.

Performance

No new recurring query or polling path is added. Runtime reads the already-loaded global value instead of querying the legacy conf_opts row, and enabled Compact Chat reduces conversation-history prompt size. Quickstart adds one settings upsert only when its Local LLM preset is applied.

Review size

25 files, 159 changed lines reported by Git; 151 are substantive and 8 are line-ending-only churn around the added sample-config line.

Limits

• Not deployed.
• The migration was not executed against a live database.
• No live HTTP/Prisma render or in-game test was performed.
• No screenshot is attached because this branch was not deployed; the settings row is generated from the validated shared catalog.