feat(memorycore): add tags system, session summaries, hook injection, tag filtering, and solidify compress mode

Implement 5 interconnected memorycore enhancements:

1. Tags backend: add tags TEXT column to memories table with migration,
   JSON array storage, full CRUD support via upsertMemory/getMemory/getMemories
2. LLM auto-tag extraction: extend extraction prompt to produce tags,
   parse and validate in pipeline, create CMEM from extraction results
3. Session summary API: expose rollout_summary via new REST endpoints
   GET /api/core-memory/sessions/summaries and sessions/:id/summary
4. Hook injection: increase SESSION_START_LIMIT to 1500, add Component 5
   (Recent Sessions) to UnifiedContextBuilder with 300-char budget
5. Tag filtering: add getMemoriesByTags() with json_each() for safe
   SQL matching, wire through MCP tool, CLI --tags flag, REST ?tags= param
6. Solidify compress mode: add --type compress to solidify.md with
   getRecentMemories(), archiveMemories(), buildCompressionMetadata()

Security fixes: safeParseTags() for corrupt DB data, json_each() instead
of LIKE injection, ESCAPE clause for searchSessionsByKeyword, singleton
store in unified-context-builder.

ccw/src/core/services/hook-context-service.ts

@@ -7,7 +7,7 @@
  *   - session-end: task generation for async background processing
  *
  * Character limits:
- *   - session-start: <= 1000 chars
+ *   - session-start: <= 1500 chars
  *   - per-prompt: <= 500 chars
  */
 
@@ -19,7 +19,7 @@ import { SessionStateService, type SessionState } from './session-state-service.
 // =============================================================================
 
 /** Maximum character count for session-start context */
-const SESSION_START_LIMIT = 1000;
+const SESSION_START_LIMIT = 1500;
 
 /** Maximum character count for per-prompt context */
 const PER_PROMPT_LIMIT = 500;