feat(kugetsu): add status, delegate, doctor commands; inject PM context at init

This commit implements Phase 3b/3c architectural improvements:

### New kugetsu CLI commands:
- `kugetsu status` - Check initialization status (replaces kugetsu-helper check-status)
- `kugetsu delegate <msg>` - Send message to PM agent (new command)
- `kugetsu doctor [--fix]` - Diagnose and fix kugetsu issues

### PM Context Injection:
- kugetsu init now reads ~/.kugetsu/pm-agent.md (if exists) and injects
  it into the PM agent session at creation time
- PM context is loaded ONCE at init, not on every delegation
- This improves efficiency - kugetsu-pm content read once, not 10 times

### kugetsu-chat updated:
- Now uses `kugetsu delegate` instead of kugetsu-helper
- Now uses `kugetsu status` instead of kugetsu-helper check-status
- Simplified - no longer depends on kugetsu-helpers

### kugetsu continue:
- Removed strict issue-ref format validation
- Now accepts any session name that is tracked in index.json["issues"]
- Issue-ref format is a guideline, not a hard requirement

### Documentation updated:
- phase3a-setup.md - Updated to reflect new kugetsu commands
- kugetsu-install.sh - Simplified Phase 3a setup instructions

### Breaking changes:
- kugetsu-helpers is no longer required for Phase 3a Chat Agent
- kugetsu-chat skill v3.0 now requires kugetsu CLI with new commands

skills/kugetsu-chat/SOUL.md

@@ -32,7 +32,7 @@ For ANY message that is not casual conversation, you MUST:
 ## Required Delegation Command
 
 ```
-terminal(command="~/.local/bin/kugetsu-helper delegate-to-pm '<user message>'", timeout=120)
+terminal(command="kugetsu delegate '<user message>'", timeout=120)
 ```
 
 ## When NOT to Delegate