feat: Meeting Assistant MVP - Complete implementation

Enterprise Meeting Knowledge Management System with:

Backend (FastAPI):
- Authentication proxy with JWT (pj-auth-api integration)
- MySQL database with 4 tables (users, meetings, conclusions, actions)
- Meeting CRUD with system code generation (C-YYYYMMDD-XX, A-YYYYMMDD-XX)
- Dify LLM integration for AI summarization
- Excel export with openpyxl
- 20 unit tests (all passing)

Client (Electron):
- Login page with company auth
- Meeting list with create/delete
- Meeting detail with real-time transcription
- Editable transcript textarea (single block, easy editing)
- AI summarization with conclusions/action items
- 5-second segment recording (efficient for long meetings)

Sidecar (Python):
- faster-whisper medium model with int8 quantization
- ONNX Runtime VAD (lightweight, ~20MB vs PyTorch ~2GB)
- Chinese punctuation processing
- OpenCC for Traditional Chinese conversion
- Anti-hallucination parameters
- Auto-cleanup of temp audio files

OpenSpec:
- add-meeting-assistant-mvp (47 tasks, archived)
- add-realtime-transcription (29 tasks, archived)

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

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

backend/app/database.py

@@ -0,0 +1,96 @@
+import mysql.connector
+from mysql.connector import pooling
+from contextlib import contextmanager
+from .config import settings
+
+connection_pool = None
+
+
+def init_db_pool():
+    global connection_pool
+    connection_pool = pooling.MySQLConnectionPool(
+        pool_name="meeting_pool",
+        pool_size=5,
+        host=settings.DB_HOST,
+        port=settings.DB_PORT,
+        user=settings.DB_USER,
+        password=settings.DB_PASS,
+        database=settings.DB_NAME,
+    )
+    return connection_pool
+
+
+@contextmanager
+def get_db_connection():
+    conn = connection_pool.get_connection()
+    try:
+        yield conn
+    finally:
+        conn.close()
+
+
+@contextmanager
+def get_db_cursor(commit=False):
+    with get_db_connection() as conn:
+        cursor = conn.cursor(dictionary=True)
+        try:
+            yield cursor
+            if commit:
+                conn.commit()
+        finally:
+            cursor.close()
+
+
+def init_tables():
+    """Create all required tables if they don't exist."""
+    create_statements = [
+        """
+        CREATE TABLE IF NOT EXISTS meeting_users (
+            user_id INT PRIMARY KEY AUTO_INCREMENT,
+            email VARCHAR(100) UNIQUE NOT NULL,
+            display_name VARCHAR(50),
+            role ENUM('admin', 'user') DEFAULT 'user',
+            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+        )
+        """,
+        """
+        CREATE TABLE IF NOT EXISTS meeting_records (
+            meeting_id INT PRIMARY KEY AUTO_INCREMENT,
+            uuid VARCHAR(64) UNIQUE,
+            subject VARCHAR(200) NOT NULL,
+            meeting_time DATETIME NOT NULL,
+            location VARCHAR(100),
+            chairperson VARCHAR(50),
+            recorder VARCHAR(50),
+            attendees TEXT,
+            transcript_blob LONGTEXT,
+            created_by VARCHAR(100),
+            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+        )
+        """,
+        """
+        CREATE TABLE IF NOT EXISTS meeting_conclusions (
+            conclusion_id INT PRIMARY KEY AUTO_INCREMENT,
+            meeting_id INT,
+            content TEXT,
+            system_code VARCHAR(20),
+            FOREIGN KEY (meeting_id) REFERENCES meeting_records(meeting_id) ON DELETE CASCADE
+        )
+        """,
+        """
+        CREATE TABLE IF NOT EXISTS meeting_action_items (
+            action_id INT PRIMARY KEY AUTO_INCREMENT,
+            meeting_id INT,
+            content TEXT,
+            owner VARCHAR(50),
+            due_date DATE,
+            status ENUM('Open', 'In Progress', 'Done', 'Delayed') DEFAULT 'Open',
+            system_code VARCHAR(20),
+            FOREIGN KEY (meeting_id) REFERENCES meeting_records(meeting_id) ON DELETE CASCADE
+        )
+        """,
+    ]
+
+    with get_db_cursor(commit=True) as cursor:
+        for statement in create_statements:
+            cursor.execute(statement)