feat: Add hookify plugin for custom hook rules via markdown

Adds the hookify plugin to public marketplace. Enables users to create custom
hooks using simple markdown configuration files instead of editing JSON.

Key features:
- Define rules with regex patterns to warn/block operations
- Create rules from explicit instructions or conversation analysis
- Pattern-based matching for bash commands, file edits, prompts, stop events
- Enable/disable rules dynamically without editing code
- Conversation analyzer agent finds problematic behaviors

Changes from internal version:
- Removed non-functional SessionStart hook (not registered in hooks.json)
- Removed all sessionstart documentation and examples
- Fixed restart documentation to consistently state "no restart needed"
- Changed license from "Internal Anthropic use only" to "MIT License"
- Kept test blocks in core modules (useful for developers)

Plugin provides:
- 4 commands: /hookify, /hookify:list, /hookify:configure, /hookify:help
- 1 agent: conversation-analyzer
- 1 skill: writing-rules
- 4 hook types: PreToolUse, PostToolUse, Stop, UserPromptSubmit
- 4 example rules ready to use

All features functional and suitable for public use.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

plugins/hookify/examples/console-log-warning.local.md

@@ -0,0 +1,14 @@
+---
+name: warn-console-log
+enabled: true
+event: file
+pattern: console\.log\(
+action: warn
+---
+
+🔍 **Console.log detected**
+
+You're adding a console.log statement. Please consider:
+- Is this for debugging or should it be proper logging?
+- Will this ship to production?
+- Should this use a logging library instead?

plugins/hookify/examples/dangerous-rm.local.md

@@ -0,0 +1,14 @@
+---
+name: block-dangerous-rm
+enabled: true
+event: bash
+pattern: rm\s+-rf
+action: block
+---
+
+⚠️ **Dangerous rm command detected!**
+
+This command could delete important files. Please:
+- Verify the path is correct
+- Consider using a safer approach
+- Make sure you have backups

plugins/hookify/examples/require-tests-stop.local.md

@@ -0,0 +1,22 @@
+---
+name: require-tests-run
+enabled: false
+event: stop
+action: block
+conditions:
+  - field: transcript
+    operator: not_contains
+    pattern: npm test|pytest|cargo test
+---
+
+**Tests not detected in transcript!**
+
+Before stopping, please run tests to verify your changes work correctly.
+
+Look for test commands like:
+- `npm test`
+- `pytest`
+- `cargo test`
+
+**Note:** This rule blocks stopping if no test commands appear in the transcript.
+Enable this rule only when you want strict test enforcement.

plugins/hookify/examples/sensitive-files-warning.local.md

@@ -0,0 +1,18 @@
+---
+name: warn-sensitive-files
+enabled: true
+event: file
+action: warn
+conditions:
+  - field: file_path
+    operator: regex_match
+    pattern: \.env$|\.env\.|credentials|secrets
+---
+
+🔐 **Sensitive file detected**
+
+You're editing a file that may contain sensitive data:
+- Ensure credentials are not hardcoded
+- Use environment variables for secrets
+- Verify this file is in .gitignore
+- Consider using a secrets manager