feat: Implement Phase 1 of SDK agent architecture with hook integration

- Added CLI commands for context, new session, save observation, and summary.
- Created HooksDatabase for managing SDK sessions and observations.
- Implemented migration 004 to add new tables: sdk_sessions, observation_queue, observations, and session_summaries.
- Developed hook functions for context display, session initialization, observation queuing, and session finalization.
- Added comprehensive tests for database schema and hook functionality.
- Documented Phase 1 implementation in PHASE1-COMPLETE.md.

src/services/sqlite/migrations.ts

@@ -202,11 +202,115 @@ export const migration003: Migration = {
   }
 };
 
+/**
+ * Migration 004 - Add SDK agent architecture tables
+ * Implements the refactor plan for hook-driven memory with SDK agent synthesis
+ */
+export const migration004: Migration = {
+  version: 4,
+  up: (db: Database) => {
+    // SDK sessions table - tracks SDK streaming sessions
+    db.run(`
+      CREATE TABLE IF NOT EXISTS sdk_sessions (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        claude_session_id TEXT UNIQUE NOT NULL,
+        sdk_session_id TEXT UNIQUE,
+        project TEXT NOT NULL,
+        user_prompt TEXT,
+        started_at TEXT NOT NULL,
+        started_at_epoch INTEGER NOT NULL,
+        completed_at TEXT,
+        completed_at_epoch INTEGER,
+        status TEXT CHECK(status IN ('active', 'completed', 'failed')) NOT NULL DEFAULT 'active'
+      );
+
+      CREATE INDEX IF NOT EXISTS idx_sdk_sessions_claude_id ON sdk_sessions(claude_session_id);
+      CREATE INDEX IF NOT EXISTS idx_sdk_sessions_sdk_id ON sdk_sessions(sdk_session_id);
+      CREATE INDEX IF NOT EXISTS idx_sdk_sessions_project ON sdk_sessions(project);
+      CREATE INDEX IF NOT EXISTS idx_sdk_sessions_status ON sdk_sessions(status);
+      CREATE INDEX IF NOT EXISTS idx_sdk_sessions_started ON sdk_sessions(started_at_epoch DESC);
+    `);
+
+    // Observation queue table - tracks pending observations for SDK processing
+    db.run(`
+      CREATE TABLE IF NOT EXISTS observation_queue (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        sdk_session_id TEXT NOT NULL,
+        tool_name TEXT NOT NULL,
+        tool_input TEXT NOT NULL,
+        tool_output TEXT NOT NULL,
+        created_at_epoch INTEGER NOT NULL,
+        processed_at_epoch INTEGER,
+        FOREIGN KEY(sdk_session_id) REFERENCES sdk_sessions(sdk_session_id) ON DELETE CASCADE
+      );
+
+      CREATE INDEX IF NOT EXISTS idx_observation_queue_sdk_session ON observation_queue(sdk_session_id);
+      CREATE INDEX IF NOT EXISTS idx_observation_queue_processed ON observation_queue(processed_at_epoch);
+      CREATE INDEX IF NOT EXISTS idx_observation_queue_pending ON observation_queue(sdk_session_id, processed_at_epoch);
+    `);
+
+    // Observations table - stores extracted observations (what SDK decides is important)
+    db.run(`
+      CREATE TABLE IF NOT EXISTS observations (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        sdk_session_id TEXT NOT NULL,
+        project TEXT NOT NULL,
+        text TEXT NOT NULL,
+        type TEXT NOT NULL CHECK(type IN ('decision', 'bugfix', 'feature', 'refactor', 'discovery')),
+        created_at TEXT NOT NULL,
+        created_at_epoch INTEGER NOT NULL,
+        FOREIGN KEY(sdk_session_id) REFERENCES sdk_sessions(sdk_session_id) ON DELETE CASCADE
+      );
+
+      CREATE INDEX IF NOT EXISTS idx_observations_sdk_session ON observations(sdk_session_id);
+      CREATE INDEX IF NOT EXISTS idx_observations_project ON observations(project);
+      CREATE INDEX IF NOT EXISTS idx_observations_type ON observations(type);
+      CREATE INDEX IF NOT EXISTS idx_observations_created ON observations(created_at_epoch DESC);
+    `);
+
+    // Session summaries table - stores structured session summaries
+    db.run(`
+      CREATE TABLE IF NOT EXISTS session_summaries (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        sdk_session_id TEXT UNIQUE NOT NULL,
+        project TEXT NOT NULL,
+        request TEXT,
+        investigated TEXT,
+        learned TEXT,
+        completed TEXT,
+        next_steps TEXT,
+        files_read TEXT,
+        files_edited TEXT,
+        notes TEXT,
+        created_at TEXT NOT NULL,
+        created_at_epoch INTEGER NOT NULL,
+        FOREIGN KEY(sdk_session_id) REFERENCES sdk_sessions(sdk_session_id) ON DELETE CASCADE
+      );
+
+      CREATE INDEX IF NOT EXISTS idx_session_summaries_sdk_session ON session_summaries(sdk_session_id);
+      CREATE INDEX IF NOT EXISTS idx_session_summaries_project ON session_summaries(project);
+      CREATE INDEX IF NOT EXISTS idx_session_summaries_created ON session_summaries(created_at_epoch DESC);
+    `);
+
+    console.log('✅ Created SDK agent architecture tables');
+  },
+
+  down: (db: Database) => {
+    db.run(`
+      DROP TABLE IF EXISTS session_summaries;
+      DROP TABLE IF EXISTS observations;
+      DROP TABLE IF EXISTS observation_queue;
+      DROP TABLE IF EXISTS sdk_sessions;
+    `);
+  }
+};
+
 /**
  * All migrations in order
  */
 export const migrations: Migration[] = [
   migration001,
   migration002,
-  migration003
+  migration003,
+  migration004
 ];