fix: GatewayConfig has no attribute 'get' when sending /start on Telegram (#973)

[Bartok9]

Problem

Sending /start to the Telegram bot triggers an AttributeError:

[Telegram] Error handling message: 'GatewayConfig' object has no attribute 'get'
Traceback (most recent call last):
  File "gateway/run.py", line 917, in _handle_message
    quick_commands = self.config.get("quick_commands", {})
AttributeError: 'GatewayConfig' object has no attribute 'get'

Root Cause

The quick_commands feature (commit 1404f84) was added to gateway/run.py but:

1. GatewayConfig dataclass didn't have a quick_commands field
2. Code used self.config.get() which doesn't work on dataclasses

Note: Commit bd2606a fixed this for CLI (cli.py), but the gateway (run.py) still had the bug.

Fix

1. Added quick_commands: Dict[str, Dict[str, Any]] field to GatewayConfig dataclass
2. Load quick_commands from config.yaml in load_gateway_config()
3. Changed self.config.get("quick_commands", {}) to getattr(self.config, "quick_commands", {})

Closes #973

[teknium1]

Thanks for the fix. This is redundant on current main now: the GatewayConfig quick-command crash path is already resolved, and the broader config-path completion work landed in PR #1287. That merged fix covers the dataclass-vs-dict access issue, adds GatewayConfig.quick_commands, and bridges quick_commands from config.yaml into gateway runtime config. Closing this one to keep the duplicate queue clean.