feat: enhanced multi-agent plan generation for Ralph wizard

- Add plan-orchestrator.ts with parallel subagent spawning
- Phase 1: 4 specialist subagents analyze in parallel (requirements, architecture, testing, risks)
- Phase 2: Synthesis merges and deduplicates outputs
- Phase 3: Verification subagent assigns priorities and identifies gaps
- New /api/generate-plan-detailed endpoint with SSE progress updates
- Auto-regenerate plan when switching between Standard/Enhanced modes
- Show quality score, warnings, and gaps from verification
- Rename "Detailed" to "Enhanced" button with tooltip

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/web/public/styles.css

@@ -5718,6 +5718,49 @@ kbd {
   text-align: left;
 }
 
+/* Quality score indicators for detailed plan mode */
+.quality-high {
+  color: #4ade80;
+  font-weight: 500;
+}
+
+.quality-medium {
+  color: #fbbf24;
+  font-weight: 500;
+}
+
+.quality-low {
+  color: #f87171;
+  font-weight: 500;
+}
+
+.mode-changed {
+  color: var(--accent);
+  font-weight: 500;
+}
+
+/* Plan warnings and gaps display */
+#planWarnings {
+  margin-bottom: 0.75rem;
+  padding: 0.5rem;
+  background: rgba(251, 191, 36, 0.1);
+  border-radius: 4px;
+  font-size: 0.8rem;
+}
+
+#planWarnings.hidden {
+  display: none;
+}
+
+.plan-gaps {
+  color: #f87171;
+  margin-bottom: 0.25rem;
+}
+
+.plan-warnings {
+  color: #fbbf24;
+}
+
 /* Textarea with AI Assist button */
 .textarea-with-assist {
   position: relative;