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.

hermes_cli/config.py

@@ -117,11 +117,22 @@ DEFAULT_CONFIG = {
         },
     },
     
+    "stt": {
+        "enabled": True,
+        "model": "whisper-1",
+    },
+    
+    "human_delay": {
+        "mode": "off",
+        "min_ms": 800,
+        "max_ms": 2500,
+    },
+    
     # Permanently allowed dangerous command patterns (added via "always" approval)
     "command_allowlist": [],
     
     # Config schema version - bump this when adding new required fields
-    "_config_version": 1,
+    "_config_version": 2,
 }
 
 # =============================================================================
@@ -195,6 +206,20 @@ OPTIONAL_ENV_VARS = {
         "url": None,
         "password": True,
     },
+    "SLACK_BOT_TOKEN": {
+        "description": "Slack bot integration",
+        "prompt": "Slack Bot Token (xoxb-...)",
+        "url": "https://api.slack.com/apps",
+        "tools": ["slack"],
+        "password": True,
+    },
+    "SLACK_APP_TOKEN": {
+        "description": "Slack Socket Mode connection",
+        "prompt": "Slack App Token (xapp-...)",
+        "url": "https://api.slack.com/apps",
+        "tools": ["slack"],
+        "password": True,
+    },
     # Messaging platform tokens
     "TELEGRAM_BOT_TOKEN": {
         "description": "Telegram bot token from @BotFather",
@@ -375,6 +400,44 @@ def migrate_config(interactive: bool = True, quiet: bool = False) -> Dict[str, A
                 results["warnings"].append(f"Skipped {var['name']} - some features may not work")
             print()
     
+    # Check for missing optional env vars and offer to configure
+    missing_optional = get_missing_env_vars(required_only=False)
+    # Filter to only truly optional ones (not already handled as required above)
+    required_names = {v["name"] for v in missing_env} if missing_env else set()
+    missing_optional = [v for v in missing_optional if v["name"] not in required_names]
+    
+    if missing_optional and not quiet:
+        print(f"\n  ℹ️  {len(missing_optional)} optional API key(s) not configured:")
+        for var in missing_optional:
+            tools = var.get("tools", [])
+            tools_str = f" → enables: {', '.join(tools)}" if tools else ""
+            print(f"     • {var['name']}: {var['description']}{tools_str}")
+    
+    if interactive and missing_optional:
+        print("\n  Would you like to configure any optional keys now?")
+        try:
+            answer = input("  Configure optional keys? [y/N]: ").strip().lower()
+        except (EOFError, KeyboardInterrupt):
+            answer = "n"
+        
+        if answer in ("y", "yes"):
+            print()
+            for var in missing_optional:
+                if var.get("url"):
+                    print(f"  Get your key at: {var['url']}")
+                
+                if var.get("password"):
+                    import getpass
+                    value = getpass.getpass(f"  {var['prompt']} (Enter to skip): ")
+                else:
+                    value = input(f"  {var['prompt']} (Enter to skip): ").strip()
+                
+                if value:
+                    save_env_value(var["name"], value)
+                    results["env_added"].append(var["name"])
+                    print(f"  ✓ Saved {var['name']}")
+                print()
+    
     # Check for missing config fields
     missing_config = get_missing_config_fields()