feat(commands): surface broken plugin warnings in /plugins list

Implements ROADMAP #40: Show warnings for broken/missing plugin manifests
instead of silently failing.

- Add PluginLoadFailure import
- New render_plugins_report_with_failures() function
- Shows ⚠️ warnings for failed plugin loads with error details
- Updates ROADMAP.md to mark #40 in progress

Ultraclaw droid session: ultraclaw-03-broken-plugins

.gitignore

@@ -5,3 +5,7 @@ archive/
 # Claude Code local artifacts
 .claude/settings.local.json
 .claude/sessions/
+# Claw Code local artifacts
+.claw/settings.local.json
+.claw/sessions/
+status-help.txt