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

app/server/Dockerfile

@@ -0,0 +1,17 @@
+# Investor Flow — Backend Dockerfile (Bun)
+FROM oven/bun:1-alpine AS backend
+
+WORKDIR /app
+
+# Install dependencies
+COPY server/package.json server/bun.lock* ./
+RUN bun install --frozen-lockfile || bun install
+
+# Copy server source
+COPY server/ ./
+
+# Expose backend port
+EXPOSE 3001
+
+# Start the server
+CMD ["bun", "run", "dev"]