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>

openspec/changes/archive/2025-12-10-add-meeting-assistant-mvp/specs/ai-summarization/spec.md

@@ -0,0 +1,45 @@
+## ADDED Requirements
+
+### Requirement: Dify Integration
+The middleware server SHALL integrate with Dify LLM at https://dify.theaken.com/v1 for transcript summarization.
+
+#### Scenario: Successful summarization
+- **WHEN** user submits POST /api/ai/summarize with transcript text
+- **THEN** the server SHALL call Dify API and return structured JSON with conclusions and action_items
+
+#### Scenario: Dify timeout handling
+- **WHEN** Dify API does not respond within timeout period
+- **THEN** the server SHALL return HTTP 504 with timeout error and client can retry
+
+#### Scenario: Dify error handling
+- **WHEN** Dify API returns error (500, rate limit, etc.)
+- **THEN** the server SHALL return appropriate HTTP error with details
+
+### Requirement: Structured Output Format
+The AI summarization SHALL return structured data with conclusions and action items.
+
+#### Scenario: Complete structured response
+- **WHEN** transcript contains clear decisions and assignments
+- **THEN** response SHALL include conclusions array and action_items array with content, owner, due_date fields
+
+#### Scenario: Partial data extraction
+- **WHEN** transcript lacks explicit owner or due_date for action items
+- **THEN** those fields SHALL be empty strings allowing manual completion
+
+### Requirement: Dify Prompt Configuration
+The Dify workflow SHALL be configured with appropriate system prompt for meeting summarization.
+
+#### Scenario: System prompt behavior
+- **WHEN** transcript is sent to Dify
+- **THEN** Dify SHALL use configured prompt to extract conclusions and action_items in JSON format
+
+### Requirement: Manual Data Completion
+The Electron client SHALL allow users to manually complete missing AI-extracted data.
+
+#### Scenario: Fill missing owner
+- **WHEN** AI returns action item without owner
+- **THEN** user SHALL be able to select or type owner name in the UI
+
+#### Scenario: Fill missing due date
+- **WHEN** AI returns action item without due_date
+- **THEN** user SHALL be able to select date using date picker