fix: Prevent duplicate workflow runs on @codebot mentions

Critical fix for workflow routing that was causing 3x duplication on every
@codebot mention. All three workflows (ai-chat, ai-comment-reply, ai-issue-triage)
were triggering simultaneously.

Changes:
- ai-issue-triage.yml: Only runs on '@codebot triage' (unchanged, already specific)
- ai-comment-reply.yml: Only runs on specific commands (help, explain, suggest, etc)
- ai-chat.yml: Only runs on free-form questions (excludes all specific commands)

Workflow routing logic:
1. '@codebot triage' → ai-issue-triage.yml ONLY
2. '@codebot <command>' → ai-comment-reply.yml ONLY
3. '@codebot <question>' → ai-chat.yml ONLY (fallback)

This prevents the massive duplication issue where every @codebot mention
triggered all three workflows simultaneously, causing 10+ redundant runs.

Updated documentation in CLAUDE.md with workflow routing architecture.

.gitea/workflows/ai-issue-triage.yml

@@ -1,5 +1,9 @@
 name: AI Issue Triage
 
+# WORKFLOW ROUTING:
+# This workflow handles ONLY the 'triage' command
+# Other workflows: ai-comment-reply.yml (specific commands), ai-chat.yml (free-form questions)
+
 on:
     issue_comment:
         types: [created]