fix: Ralph Loop wizard screen creation and session idle detection

- Fix screen creation failing when using cpulimit/nice (env vars were passed
  as command args instead of shell variables)
- Fix session status never becoming 'idle' after startInteractive()
- Add automatic state file cleanup on startup (removes orphaned sessions)
- Add /api/cleanup-state endpoint for manual cleanup
- Make frontend session readiness check more robust (20 attempts, multiple checks)
- Add fallback to direct PTY write if writeViaScreen fails

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

src/web/public/styles.css

@@ -5433,6 +5433,68 @@ kbd {
   justify-content: center;
 }
 
+/* Existing Plan Badge (in case selector) */
+.existing-plan-badge {
+  font-size: 0.7rem;
+  background: var(--accent);
+  color: white;
+  padding: 0.1rem 0.4rem;
+  border-radius: 3px;
+  margin-left: 0.5rem;
+  font-weight: normal;
+}
+
+/* Existing Plan Card (Step 2) */
+.existing-plan-card {
+  background: var(--bg-input);
+  border: 1px solid var(--accent);
+  border-radius: 6px;
+  padding: 1rem;
+  text-align: left;
+}
+
+.existing-plan-header {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  font-weight: 500;
+  margin-bottom: 0.75rem;
+}
+
+.existing-plan-icon {
+  font-size: 1.2rem;
+}
+
+.existing-plan-stats {
+  display: flex;
+  gap: 1rem;
+  margin-bottom: 1rem;
+  font-size: 0.85rem;
+}
+
+.existing-plan-stats .stat {
+  display: flex;
+  align-items: center;
+  gap: 0.25rem;
+}
+
+.existing-plan-stats .stat.pending {
+  color: var(--yellow);
+}
+
+.existing-plan-stats .stat.completed {
+  color: var(--green);
+}
+
+.existing-plan-stats .stat.total {
+  color: var(--text-muted);
+}
+
+.existing-plan-actions {
+  display: flex;
+  gap: 0.5rem;
+}
+
 /* Plan Loading State */
 .plan-loading-state {
   padding: 1.5rem 1rem;
@@ -5563,6 +5625,13 @@ kbd {
   font-size: 0.9rem;
 }
 
+.plan-stats {
+  font-weight: normal;
+  font-size: 0.8rem;
+  color: var(--text-muted);
+  margin-left: 0.5rem;
+}
+
 .plan-editor-actions {
   display: flex;
   gap: 0.35rem;
@@ -5572,7 +5641,7 @@ kbd {
   display: flex;
   flex-direction: column;
   gap: 0.35rem;
-  max-height: 160px;
+  max-height: 300px;
   overflow-y: auto;
   margin-bottom: 0.5rem;
 }