fix: complete better-sqlite3 to bun:sqlite migration

Must Fix:
- Remove better-sqlite3 logic from smart-install.js (5 sections)
- Update all documentation to reference bun:sqlite (7 files)

Should Fix:
- Add defensive break statement in worker-cli.ts:38

Nice to Have:
- Add port validation in ProcessManager.start() (1024-65535)
- Add one-time marker for PM2 cleanup migration
- Verify clearPortCache() wiring (already correct)

Addresses PR #248 review feedback (comment #3648517713)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

docs/public/architecture/overview.mdx

@@ -22,7 +22,7 @@ Claude-Mem operates as a Claude Code plugin with five core components:
 |------------------------|-------------------------------------------|
 | **Language**           | TypeScript (ES2022, ESNext modules)       |
 | **Runtime**            | Node.js 18+                               |
-| **Database**           | SQLite 3 with better-sqlite3 driver       |
+| **Database**           | SQLite 3 with bun:sqlite driver           |
 | **Vector Store**       | ChromaDB (optional, for semantic search)  |
 | **HTTP Server**        | Express.js 4.18                           |
 | **Real-time**          | Server-Sent Events (SSE)                  |
@@ -205,7 +205,7 @@ Express.js HTTP server on port 37777 (configurable) with:
 See [Worker Service](/architecture/worker-service) for HTTP API and endpoints.
 
 ### 3. Database Layer
-SQLite3 with better-sqlite3 driver featuring:
+SQLite3 with bun:sqlite driver featuring:
 - FTS5 virtual tables for full-text search
 - SessionStore for CRUD operations
 - SessionSearch for FTS5 queries