fix #16: cleanup - remove old/dead code and update docs

- Delete apps/telegram-bot/storage.py (replaced by adapters/storage/json_file.py)
- Delete apps/telegram-bot/__init__.py (empty file)
- Delete apps/telegram-bot/requirements-dev.txt (dev deps in pyproject.toml)
- Update SPEC.md with new hexagonal architecture (core, adapters, apps)
- Update SPEC.md command reference: /update -> /edit
- Update README.md with new project structure and quick start
- Update CONTRIBUTING.md with new architecture and dev setup

SPEC.md

@@ -20,7 +20,7 @@ JIGAIDO is a Telegram bot that lets groups and individuals track bounties — ta
 
 ### Stack
 - **Bot**: `python-telegram-bot` (pure Python, no C extensions)
-- **Storage**: Per-group JSON files (zero-setup, no DB server)
+- **Storage**: Per-group JSON files via `adapters/storage/json_file.py`
 - **Date parsing**: `dateparser`
 - **Runtime**: Python 3.10+
 - **Deployment**: Any $5 VPS with Python 3.10+
@@ -28,19 +28,40 @@ JIGAIDO is a Telegram bot that lets groups and individuals track bounties — ta
 ### Directory Structure
 
 ```
-~/.jigaido/                          # Data root (~/.jigaido/)
-├── {group_id}/
-│   ├── group.json                  # Group bounties
-│   └── {user_id}.json              # User tracking within this group
-└── {user_id}/
-    └── user.json                    # User's personal bounties (DM mode)
+jigaido/
+├── core/                    # Domain layer
+│   ├── models.py            # Domain dataclasses (Bounty, Tracking)
+│   ├── ports.py             # Port interfaces (abstract base classes)
+│   └── services.py          # Domain services (BountyService, TrackingService)
+├── adapters/                # Infrastructure adapters
+│   └── storage/
+│       └── json_file.py     # JSON file storage implementation
+├── apps/
+│   └── telegram-bot/        # Telegram bot CLI application
+│       ├── bot.py            # Bot entry point
+│       └── commands.py       # Command handlers
+├── config.py               # Configuration management
+└── tests/                  # Unit tests
 ```
 
-**Note:** Data directory is at `~/.jigaido/` (home directory), NOT inside the repository or app directory.
+### Hexagonal Architecture
 
-### Storage Design
+- **Core** (`core/`): Pure domain logic, no external dependencies
+  - `models.py`: Domain dataclasses
+  - `ports.py`: Abstract interfaces for storage
+  - `services.py`: Business logic
 
-**File: `data/{group_id}/group.json`**
+- **Adapters** (`adapters/`): Implementations of ports
+  - `storage/json_file.py`: JSON file-based storage
+
+- **Apps** (`apps/`): CLI applications
+  - `telegram-bot/`: Telegram bot interface
+
+### Data Storage
+
+Data is stored at `~/.jigaido/` (home directory), NOT inside the repository.
+
+**File: `~/.jigaido/{group_id}/group.json`**
 
 ```json
 {
@@ -58,7 +79,7 @@ JIGAIDO is a Telegram bot that lets groups and individuals track bounties — ta
 }
 ```
 
-**File: `data/{group_id}/{user_id}.json`**
+**File: `~/.jigaido/{group_id}/{user_id}.json`**
 
 ```json
 {
@@ -68,7 +89,7 @@ JIGAIDO is a Telegram bot that lets groups and individuals track bounties — ta
 }
 ```
 
-**File: `data/{user_id}/user.json`**
+**File: `~/.jigaido/{user_id}/user.json`**
 
 ```json
 {
@@ -87,10 +108,10 @@ JIGAIDO is a Telegram bot that lets groups and individuals track bounties — ta
 
 **Key design decisions:**
 
-1. **Group-isolated storage** — Each group has its own directory. No cross-group access.
-2. **Bounty IDs are sequential per group.json** — Not global. Each group's file has its own ID counter.
-3. **Atomic writes** — Uses `tempfile` + `rename` for safe writes.
-4. **No reminders in v1** — Dropped for simplicity.
+1. **Hexagonal architecture** — Core domain is isolated from infrastructure
+2. **Group-isolated storage** — Each group has its own directory. No cross-group access.
+3. **Bounty IDs are sequential per group.json** — Not global. Each group's file has its own ID counter.
+4. **Atomic writes** — Uses `tempfile` + `rename` for safe writes.
 
 ---
 ## Commands
@@ -102,7 +123,7 @@ JIGAIDO is a Telegram bot that lets groups and individuals track bounties — ta
 | `/bounty` | anyone | List all bounties in this group |
 | `/my` | anyone | List bounties tracked by you in this group |
 | `/add <text> [link] [due date]` | anyone | Add a new bounty to the group |
-| `/update <bounty_id> [text] [link] [due_date]` | creator only | Update an existing bounty |
+| `/edit <bounty_id> [text] [link] [due_date]` | creator only | Edit an existing bounty |
 | `/delete <bounty_id>` | creator only | Delete a bounty |
 | `/track <bounty_id>` | anyone | Track a group bounty |
 | `/untrack <bounty_id>` | anyone | Stop tracking a bounty |
@@ -114,7 +135,7 @@ JIGAIDO is a Telegram bot that lets groups and individuals track bounties — ta
 | `/bounty` | List all your personal bounties |
 | `/my` | List all your personal bounties |
 | `/add <text> [link] [due date]` | Add a personal bounty |
-| `/update <bounty_id> [text] [link] [due_date]` | Update a personal bounty |
+| `/edit <bounty_id> [text] [link] [due_date]` | Edit a personal bounty |
 | `/delete <bounty_id>` | Delete a personal bounty |
 | `/track <bounty_id>` | Track a personal bounty |
 
@@ -149,7 +170,7 @@ Stored as Unix timestamp. User-facing display can be localized/converted to any
 ## Error Handling
 
 - Unknown command → help text with available commands
-- `/update`/`/delete` by non-creator → "⛔ Only the creator can edit/delete this bounty."
+- `/edit`/`/delete` by non-creator → "⛔ Only the creator can edit/delete this bounty."
 - `/track` already tracked → "Already tracking" (idempotent)
 - `/untrack` not tracked → "Not tracking" (idempotent)
 - Bounty not found → "Bounty not found"