Add Phase 12: native RPG world state

Structured world/player/NPC stats, two-way flags, and sticky milestones
per scenario (stat_schema). The AI proposes a per-turn delta; a Python
engine referees it (clamp to min/max, per-turn cap, cooldown, counters).
Band word-labels plus a fixed stat guide (descriptions + full ranges)
keep the model grounded. World State drawer + Insights delta report;
undo/retry roll it back via the Phase 11 snapshot pattern.

- migrations 26-28 (scenarios.stat_schema, adventures.world_state,
  actions.world_state_before); all nullable, additive, safe on existing rows
- migration 29 raises the default context budget 4096 -> 16384
  (custom values preserved)
- seeded demo scenario 04-rpg-world-state.json (Bandit Camp)
- 19 new tests (33 total pass)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/index.css

@@ -576,6 +576,96 @@ button:disabled { opacity: 0.45; cursor: default; transform: none; box-shadow: n
   from { opacity: 0; transform: translateX(16px); }
   to { opacity: 1; transform: none; }
 }
+
+/* ---------- World State drawer (Phase 12 RPG) ---------- */
+.ws-group { margin-bottom: 18px; }
+.ws-group-title {
+  font-size: 0.72rem;
+  text-transform: uppercase;
+  letter-spacing: 0.1em;
+  color: var(--text-dim);
+  margin: 0 0 8px;
+}
+.ws-stat { padding: 5px 0; }
+.ws-stat-head {
+  display: flex;
+  justify-content: space-between;
+  align-items: baseline;
+  gap: 8px;
+  font-size: 0.85rem;
+}
+.ws-stat-name { color: var(--text); text-transform: capitalize; }
+.ws-stat-val {
+  color: var(--text-dim);
+  font-variant-numeric: tabular-nums;
+  font-size: 0.8rem;
+  text-align: right;
+}
+.ws-band { color: var(--accent-bright); }
+.ws-bar {
+  margin-top: 4px;
+  height: 5px;
+  border-radius: 3px;
+  background: var(--bg-input);
+  overflow: hidden;
+}
+.ws-bar-fill {
+  height: 100%;
+  border-radius: 3px;
+  background: var(--accent);
+  transition: width 0.35s ease;
+}
+.ws-milestones { list-style: none; margin: 0; padding: 0; }
+.ws-milestones li {
+  display: flex;
+  gap: 7px;
+  align-items: flex-start;
+  padding: 4px 0;
+  font-size: 0.85rem;
+  color: var(--text);
+}
+.ws-milestones li.done { color: var(--text-dim); }
+.ws-check { flex-shrink: 0; color: var(--accent-bright); }
+.ws-milestones li.done .ws-check { color: var(--player); }
+.ws-flags { list-style: none; margin: 0; padding: 0; }
+.ws-flags li {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 4px 0;
+  font-size: 0.85rem;
+  color: var(--text);
+}
+.ws-flag-dot {
+  width: 9px; height: 9px; border-radius: 50%;
+  flex-shrink: 0;
+  background: var(--bg-input);
+  border: 1px solid var(--border);
+}
+.ws-flag-dot.on { background: var(--accent); border-color: var(--accent); }
+.ws-flag-name { flex: 1; }
+.ws-flag-val { color: var(--text-dim); font-size: 0.8rem; }
+
+.schema-editor {
+  width: 100%;
+  font-family: var(--font-mono, monospace);
+  font-size: 0.82rem;
+  line-height: 1.5;
+  tab-size: 2;
+  white-space: pre;
+  overflow-x: auto;
+}
+.schema-error {
+  margin-top: 6px;
+  color: var(--danger, #e5484d);
+  font-size: 0.82rem;
+}
+.ws-report { list-style: none; margin: 4px 0 0; padding: 0; font-size: 0.82rem; }
+.ws-report li { padding: 2px 0; color: var(--text); }
+.ws-report code { color: var(--accent-bright); }
+.ws-delta { color: var(--player); font-variant-numeric: tabular-nums; }
+.ws-flag { color: var(--text-dim); font-style: italic; }
+.ws-rejected { color: var(--text-dim); }
 .side-panel-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 16px; }
 .side-panel-header h2 {
   margin: 0;