Add messaging platform enhancements: STT, stickers, Discord UX, Slack, pairing, hooks

Major feature additions inspired by OpenClaw/ClawdBot integration analysis:

Voice Message Transcription (STT):
- Auto-transcribe voice/audio messages via OpenAI Whisper API
- Download voice to ~/.hermes/audio_cache/ on Telegram/Discord/WhatsApp
- Inject transcript as text so all models can understand voice input
- Configurable model (whisper-1, gpt-4o-mini-transcribe, gpt-4o-transcribe)

Telegram Sticker Understanding:
- Describe static stickers via vision tool with JSON-backed cache
- Cache keyed by file_unique_id avoids redundant API calls
- Animated/video stickers get emoji-based fallback description

Discord Rich UX:
- Native slash commands (/ask, /reset, /status, /stop) via app_commands
- Button-based exec approvals (Allow Once / Always Allow / Deny)
- ExecApprovalView with user authorization and timeout handling

Slack Integration:
- Full SlackAdapter using slack-bolt with Socket Mode
- DMs, channel messages (mention-gated), /hermes slash command
- File attachment handling with bot-token-authenticated downloads

DM Pairing System:
- Code-based user authorization as alternative to static allowlists
- 8-char codes from unambiguous alphabet, 1-hour expiry
- Rate limiting, lockout after failed attempts, chmod 0600 on data
- CLI: hermes pairing list/approve/revoke/clear-pending

Event Hook System:
- File-based hook discovery from ~/.hermes/hooks/
- HOOK.yaml + handler.py per hook, sync/async handler support
- Events: gateway:startup, session:start/reset, agent:start/step/end
- Wildcard matching (command:* catches all command events)

Cross-Channel Messaging:
- send_message agent tool for delivering to any connected platform
- Enables cron job delivery and cross-platform notifications

Human-Like Response Pacing:
- Configurable delays between message chunks (off/natural/custom)
- HERMES_HUMAN_DELAY_MODE env var with min/max ms settings

Warm Injection Message Style:
- Retrofitted image vision messages with friendly kawaii-consistent tone
- All new injection messages (STT, stickers, errors) use warm style

Also: updated config migration to prompt for optional keys interactively,
bumped config version, updated README, AGENTS.md, .env.example,
cli-config.yaml.example, install scripts, pyproject.toml, and toolsets.

README.md

@@ -80,6 +80,8 @@ You need at least one LLM provider:
 | Premium TTS voices | [ElevenLabs](https://elevenlabs.io/) | `ELEVENLABS_API_KEY` |
 | OpenAI TTS voices | [OpenAI](https://platform.openai.com/api-keys) | `OPENAI_API_KEY` |
 | RL Training | [Tinker](https://tinker-console.thinkingmachines.ai/) + [WandB](https://wandb.ai/) | `TINKER_API_KEY`, `WANDB_API_KEY` |
+| Voice transcription | [OpenAI](https://platform.openai.com/api-keys) | `OPENAI_API_KEY` |
+| Slack integration | [Slack](https://api.slack.com/apps) | `SLACK_BOT_TOKEN`, `SLACK_APP_TOKEN` |
 | Messaging | Telegram, Discord | `TELEGRAM_BOT_TOKEN`, `DISCORD_BOT_TOKEN` |
 
 ---
@@ -99,6 +101,7 @@ hermes update             # Update to latest version (prompts for new config)
 hermes uninstall          # Uninstall (can keep configs for later reinstall)
 hermes gateway            # Start messaging gateway
 hermes cron list          # View scheduled jobs
+hermes pairing list       # View/manage DM pairing codes
 hermes version            # Show version info
 ```
 
@@ -176,6 +179,23 @@ sudo dnf install ffmpeg
 
 Without ffmpeg, Edge TTS audio is sent as a regular audio file (playable, but shows as a rectangular player instead of a voice bubble). If you want voice bubbles without installing ffmpeg, switch to the OpenAI or ElevenLabs provider.
 
+### 🎙️ Voice Message Transcription
+
+Voice messages sent on Telegram, Discord, WhatsApp, or Slack are automatically transcribed using OpenAI's Whisper API and injected as text into the conversation. The agent sees the transcript as normal text -- no special handling needed.
+
+| Provider | Model | Quality | Cost |
+|----------|-------|---------|------|
+| **OpenAI Whisper** | `whisper-1` (default) | Good | Low |
+| **OpenAI GPT-4o** | `gpt-4o-mini-transcribe` | Better | Medium |
+| **OpenAI GPT-4o** | `gpt-4o-transcribe` | Best | Higher |
+
+Requires `OPENAI_API_KEY` in `~/.hermes/.env`. Configure the model in `~/.hermes/config.yaml`:
+```yaml
+stt:
+  enabled: true
+  model: "whisper-1"
+```
+
 ### 📄 Context Files (SOUL.md, AGENTS.md, .cursorrules)
 
 Drop these files in your project directory and the agent automatically picks them up:
@@ -293,6 +313,40 @@ DISCORD_BOT_TOKEN=MTIz...
 DISCORD_ALLOWED_USERS=YOUR_USER_ID
 ```
 
+#### Slack Setup
+
+1. **Create an app:** Go to [Slack API](https://api.slack.com/apps), create a new app
+2. **Enable Socket Mode:** In app settings → Socket Mode → Enable
+3. **Get tokens:**
+   - Bot Token (`xoxb-...`): OAuth & Permissions → Install to Workspace
+   - App Token (`xapp-...`): Basic Information → App-Level Tokens → Generate
+4. **Configure:**
+
+```bash
+# Add to ~/.hermes/.env:
+SLACK_BOT_TOKEN=xoxb-...
+SLACK_APP_TOKEN=xapp-...
+SLACK_ALLOWED_USERS=U01234ABCDE    # Comma-separated Slack user IDs
+```
+
+5. **Start the gateway:** `hermes gateway`
+
+#### DM Pairing (Alternative to Allowlists)
+
+Instead of manually configuring user IDs in allowlists, you can use the pairing system. When an unknown user DMs your bot, they receive a one-time pairing code:
+
+```bash
+# The user sees: "Pairing code: XKGH5N7P"
+# You approve them with:
+hermes pairing approve telegram XKGH5N7P
+
+# Other pairing commands:
+hermes pairing list          # View pending + approved users
+hermes pairing revoke telegram 123456789  # Remove access
+```
+
+Pairing codes expire after 1 hour, are rate-limited, and use cryptographic randomness.
+
 #### Security (Important!)
 
 **Without an allowlist, anyone who finds your bot can use it!**
@@ -312,6 +366,7 @@ DISCORD_ALLOWED_USERS=123456789012345678
 |---------|-------------|
 | `/new` or `/reset` | Start fresh conversation |
 | `/status` | Show session info |
+| `/hermes` (Discord) | Slash command — ask, reset, status, stop |
 
 #### Working Directory