Add implementation plan to docs

Copied from planning phase - full specification for PTY wrapper,
WebSocket protocol, SQLite schema, and deployment setup.

docs/plan.md

@@ -0,0 +1,157 @@
+# claude-remote
+
+self-hosted remote control for claude code, pure bun stack.
+
+## summary
+
+wrap claude cli in PTY, stream output to server, approve prompts from phone.
+
+## tech stack
+
+- bun-pty (native PTY via FFI to Rust)
+- bun:sqlite (persistence)
+- Bun.serve() (HTTP + WebSocket + SSE)
+- no frameworks
+
+## project location
+
+`/home/jtm/projects/agentry/repos/claude-remote/`
+
+## structure
+
+```
+claude-remote/
+├── src/
+│   ├── cli.ts           # PTY wrapper, connects to server
+│   ├── server.ts        # HTTP + WebSocket + SSE
+│   ├── db.ts            # SQLite schema + queries
+│   ├── auth.ts          # HMAC signing
+│   └── types.ts         # shared types
+├── public/
+│   └── index.html       # mobile dashboard
+├── docs/
+│   └── plan.md          # this plan (moved here)
+├── CLAUDE.md
+├── package.json
+├── Dockerfile
+├── compose.yml
+└── justfile
+```
+
+## sqlite schema
+
+```sql
+CREATE TABLE devices (
+  id INTEGER PRIMARY KEY,
+  secret TEXT NOT NULL UNIQUE,
+  name TEXT,
+  created_at INTEGER NOT NULL,
+  last_seen INTEGER NOT NULL
+);
+
+CREATE TABLE sessions (
+  id INTEGER PRIMARY KEY,
+  device_id INTEGER NOT NULL,
+  started_at INTEGER NOT NULL,
+  ended_at INTEGER,
+  cwd TEXT,
+  command TEXT
+);
+
+CREATE TABLE prompts (
+  id INTEGER PRIMARY KEY,
+  session_id INTEGER NOT NULL,
+  created_at INTEGER NOT NULL,
+  prompt_text TEXT NOT NULL,
+  response TEXT,
+  responded_at INTEGER
+);
+
+CREATE TABLE output_log (
+  id INTEGER PRIMARY KEY,
+  session_id INTEGER NOT NULL,
+  timestamp INTEGER NOT NULL,
+  line TEXT NOT NULL
+);
+```
+
+## api
+
+REST:
+- `GET /` - dashboard
+- `GET /api/sessions` - list sessions
+- `POST /api/prompts/:id/approve` - approve
+- `POST /api/prompts/:id/reject` - reject
+
+WebSocket `/ws` (CLI <-> Server):
+- cli sends: auth, output, resize, exit
+- server sends: input, resize, ping
+
+SSE `/events` (Server -> Dashboard):
+- session_start, session_end, output, prompt, prompt_response
+
+## implementation phases
+
+### phase 1: foundation (~300 lines)
+1. create project structure
+2. `src/types.ts` - message types
+3. `src/db.ts` - sqlite schema + queries
+4. `src/auth.ts` - device secret + HMAC
+
+### phase 2: server (~250 lines)
+5. `src/server.ts` - Bun.serve with routes
+6. WebSocket handler for CLI
+7. SSE endpoint for viewers
+8. REST endpoints for approval
+
+### phase 3: cli wrapper (~150 lines)
+9. `src/cli.ts` - spawn claude with bun-pty
+10. WebSocket client to server
+11. forward PTY output, handle resize
+
+### phase 4: dashboard (~300 lines)
+12. `public/index.html` - mobile-first
+13. SSE listener
+14. terminal output display
+15. approve/reject buttons
+
+### phase 5: deployment (~100 lines)
+16. Dockerfile (oven/bun)
+17. compose.yml with volume
+18. justfile commands
+19. error handling + reconnection
+
+## key decisions
+
+- bun-pty over node-pty: pure FFI, pre-built binaries
+- SQLite over in-memory: persistence across restarts
+- SSE over WebSocket for dashboard: simpler, auto-reconnect
+- HMAC over TLS certs: simpler deployment
+- plain text output over xterm.js: mobile-friendly, simpler
+
+## verification
+
+1. `bun run src/cli.ts` - starts PTY wrapper
+2. visit `http://localhost:3000` - see dashboard
+3. type in CLI - output appears in dashboard
+4. trigger approval prompt - approve from dashboard
+5. `docker compose up` - deploys successfully
+
+## dependencies
+
+```json
+{
+  "dependencies": {
+    "bun-pty": "^0.4.8"
+  }
+}
+```
+
+that's it. one external dep.
+
+## CLAUDE.md notes
+
+- if bun-pty needs changes, fork and contribute upstream
+- use bun:sqlite, not better-sqlite3
+- no frameworks (no express, no hono)
+- target ~1000-1500 lines total