Add auto-slash-command hook for intercepting and replacing slash commands

This hook intercepts user messages starting with '/' and REPLACES them with the actual command template output instead of injecting instructions. The implementation includes:

- Slash command detection (detector.ts) - identifies messages starting with '/'
- Command discovery and execution (executor.ts) - loads templates from ~/.claude/commands/ or similar
- Hook integration (index.ts) - registers with chat.message event to replace output.parts
- Comprehensive test coverage - 37 tests covering detection, replacement, error handling, and command exclusions
- Configuration support in HookNameSchema

Key features:
- Supports excluded commands to skip processing
- Loads command templates from user's command directory
- Replaces user input before reaching the LLM
- Tests all edge cases including missing files, malformed templates, and special commands

🤖 Generated with assistance of OhMyOpenCode (https://github.com/code-yeongyu/oh-my-opencode)

src/hooks/auto-slash-command/constants.ts

@@ -0,0 +1,11 @@
+export const HOOK_NAME = "auto-slash-command" as const
+
+export const AUTO_SLASH_COMMAND_TAG_OPEN = "<auto-slash-command>"
+export const AUTO_SLASH_COMMAND_TAG_CLOSE = "</auto-slash-command>"
+
+export const SLASH_COMMAND_PATTERN = /^\/([a-zA-Z][\w-]*)\s*(.*)/
+
+export const EXCLUDED_COMMANDS = new Set([
+  "ralph-loop",
+  "cancel-ralph",
+])