Updates slash cmd to observers to filter on specific commands

[3coins]

Summary

Enhances the MessageRouter to support command-specific slash command observers with flexible pattern matching. This allows observers to register for specific commands rather than receiving all slash commands.

Key Changes

• Updated observe_slash_cmd_msg() to accept a command_pattern parameter for filtering specific commands
• Supports exact matches ("help"), wildcards ("ai-*"), and regex patterns ("export-(json|csv)")
• Automatically strips the command from message body and passes clean command name to callbacks
• Updated callback signature to (room_id: str, command: str, message: Message) where command is the clean command name and message.body contains only the arguments

New Features

1. Command Filtering: Observers only receive messages for commands matching their registered patterns
2. Flexible Matching: Three pattern types supported for different use cases
3. Clean API: Commands passed without leading slash, message bodies contain only arguments
4. Metadata Preservation: All original message metadata is preserved in the trimmed message

Example Usage

# Exact command match
router.observe_slash_cmd_msg("room1", "help", handle_help)

# Wildcard pattern for command families  
router.observe_slash_cmd_msg("room1", "ai-*", handle_ai_commands)

# Regex pattern for specific variants
router.observe_slash_cmd_msg("room1", r"export-(json|csv)", handle_exports)

Breaking Changes

The observe_slash_cmd_msg() method signature has changed from (room_id, callback) to (room_id, command_pattern, callback) and callback signature changed from (room_id, message) to (room_id, command, message).

Fixes #7

[3coins]

cc @Zsailer @jtpio

[dlqqq]

@3coins Thank you Piyush! The code looks good, appreciate the unit tests that verify this logic.

I left a few comments below, but none of these are blocking since the code works as-is. 👋

[dlqqq]

✅ Looks perfect!