S56: spawn template overhaul + system-wide README push + .gitkeep cleanup (#129)

- Spawn template system rebuilt: regenerate-registry command (3-pass ID matching),
  registry 26→41 files, generate_branch_meta fixed, Phase 0 snapshot added
- System-wide push: 12/12 branches updated (227 additions, 0 errors)
- READMEs added to all standard directories across 15 branches
- .claude/settings.local.json tracked system-wide (deny rules)
- 35 .gitkeep files removed (replaced by READMEs)
- Bypass files updated across 13 branches
- Bugs fixed: manager citizen_class crash, backup rglob performance

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/aipass/spawn/apps/spawn.py

@@ -43,7 +43,7 @@ def print_help():
     console.print("  [green]delete[/green] <@branch>              Archive and deregister branch")
     console.print("  [green]sync-registry[/green]                 Repair registry against filesystem")
     console.print("  [green]sync-templates[/green]                Pull managed files from source")
-    console.print("  [dim]regenerate-registry[/dim]           Regenerate template registry hashes [dim][not yet implemented][/dim]")
+    console.print("  [green]regenerate-registry[/green]           Regenerate template registry hashes")
     console.print()
     console.print("[bold cyan]CITIZEN CLASSES:[/bold cyan]")
     console.print()
@@ -130,6 +130,7 @@ def print_introspection():
     console.print("    - delete.py (handle_delete — archive and deregister branch)")
     console.print("    - sync_registry.py (handle_sync_registry — registry repair)")
     console.print("    - sync_templates.py (handle_sync_templates — template synchronization)")
+    console.print("    - regenerate_registry.py (handle_regenerate_registry — regenerate template registry)")
     console.print("    - passport.py (handle_passport — grant birthright citizenship)")
     console.print()
 
@@ -176,14 +177,9 @@ def main():
         from aipass.spawn.apps.modules.passport import handle_passport
         return handle_passport(remaining)
 
-    # Stub commands — planned but not yet implemented
-    stub_commands = {
-        "regenerate-registry": "Regenerate template registry hashes",
-    }
-
-    if command in stub_commands:
-        warning(f"'{command}' is not yet implemented.", details=f"Planned: {stub_commands[command]}")
-        return 1
+    if command == "regenerate-registry":
+        from aipass.spawn.apps.modules.regenerate_registry import handle_regenerate_registry
+        return handle_regenerate_registry(remaining)
 
     error(f"Unknown command: {command}", suggestion="Run 'drone @spawn --help' for available commands")
     return 1