refactor: require Bun globally, add auto-install, remove Windows executable approach (#243)

- Delete BinaryManager.ts - no longer needed
- Simplify ProcessManager.ts - single Bun spawn path for all platforms
- Update smart-install.js - auto-install Bun if missing (Windows/Unix)
- Update documentation to reflect Bun requirement

This simplifies the codebase by:
- Using Bun consistently across all platforms (hooks + worker)
- Eliminating binary download/hosting complexity
- Zero native dependencies with bun:sqlite
- Auto-installing Bun on first run if not present

Co-authored-by: Claude <noreply@anthropic.com>

README.md

@@ -108,7 +108,7 @@ npx mintlify dev
 - **[Architecture Evolution](https://docs.claude-mem.ai/architecture-evolution)** - The journey from v3 to v5
 - **[Hooks Architecture](https://docs.claude-mem.ai/hooks-architecture)** - How Claude-Mem uses lifecycle hooks
 - **[Hooks Reference](https://docs.claude-mem.ai/architecture/hooks)** - 7 hook scripts explained
-- **[Worker Service](https://docs.claude-mem.ai/architecture/worker-service)** - HTTP API & PM2 management
+- **[Worker Service](https://docs.claude-mem.ai/architecture/worker-service)** - HTTP API & Bun process management
 - **[Database](https://docs.claude-mem.ai/architecture/database)** - SQLite schema & FTS5 search
 - **[Search Architecture](https://docs.claude-mem.ai/architecture/search-architecture)** - Hybrid search with Chroma vector database
 
@@ -148,7 +148,7 @@ npx mintlify dev
 
 1. **5 Lifecycle Hooks** - SessionStart, UserPromptSubmit, PostToolUse, Stop, SessionEnd (6 hook scripts)
 2. **Smart Install** - Cached dependency checker (pre-hook script, not a lifecycle hook)
-3. **Worker Service** - HTTP API on port 37777 with web viewer UI and 10 search endpoints, managed by PM2
+3. **Worker Service** - HTTP API on port 37777 with web viewer UI and 10 search endpoints, managed by Bun
 4. **SQLite Database** - Stores sessions, observations, summaries with FTS5 full-text search
 5. **mem-search Skill** - Natural language queries with progressive disclosure (~2,250 token savings vs MCP)
 6. **Chroma Vector Database** - Hybrid semantic + keyword search for intelligent context retrieval
@@ -260,10 +260,10 @@ See [CHANGELOG.md](CHANGELOG.md) for complete version history.
 
 ## System Requirements
 
-- **Node.js**: 18.0.0 or higher
+- **Bun**: 1.0 or higher (auto-installed on first run if missing)
+- **Node.js**: 18.0.0 or higher (for build tools)
 - **Claude Code**: Latest version with plugin support
-- **PM2**: Process manager (bundled - no global install required)
-- **SQLite 3**: For persistent storage (bundled)
+- **SQLite 3**: For persistent storage (via bun:sqlite - zero native dependencies)
 
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