fix: backfill symbol_demand for sidebar-added symbols + analyst ratings schema fix

- Add await ctx.cache.subscribe() to addSymbol mutation so symbols
  added via the sidebar get registered in symbol_demand and yfinance
  jobs are queued immediately
- Backfill PEP, WYNN, STZ, CELH into symbol_demand + adapter_queue
- Upgrade yahoo-finance2 3.15.3 -> 3.15.4 and pass validateResult:false
  to quoteSummary() to handle Yahoo schema drift
- Add error detail logging for analyst ratings schema failures
- Update .gitignore with common ignores

.automaton/loops/symbol-header/loop.json

@@ -0,0 +1,35 @@
+{
+  "name": "symbol-header",
+  "description": "Triage CI failures: research, decompose, propose fix.",
+  "schedule": {
+    "interval_seconds": 3600
+  },
+  "brakes": {
+    "max_iterations": 25,
+    "max_budget_usd": null,
+    "score_plateau_window": 5
+  },
+  "blast_radius": {
+    "file_scope": [],
+    "use_worktree": true
+  },
+  "work_source": {
+    "kind": "single"
+  },
+  "acceptance_criteria": [
+    "All R-numbers from SPEC.md are implemented.",
+    "Tests pass with no regressions.",
+    "Pipeline driven to complete."
+  ],
+  "roles": {
+    "implement": {
+      "prompt": "loop-implement.md"
+    },
+    "verify": {
+      "prompt": "loop-verifier.md"
+    },
+    "orchestrate": {
+      "prompt": "loop-orchestrate.md"
+    }
+  }
+}