feat: add persistent Deno cache to Railway executor for faster tool loading

- Set DENO_DIR=/app/.deno_cache to persist module cache
- Pre-cache common dependencies (zod-to-json-schema, ai, zod) during build
- Add Railway volume configuration for /app/.deno_cache
- Improve logging to show cache hits vs network downloads
- Add --allow-read and --allow-write permissions for cache access

This dramatically reduces tool loading time after the first import.
Dependencies are downloaded once and reused across all subsequent requests.

Example: ctx-zip with 200+ dependencies will only download once instead
of on every chat request.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps/railway-executor/Dockerfile

@@ -4,11 +4,27 @@ FROM denoland/deno:1.39.0
 # Set working directory
 WORKDIR /app
 
-# Copy the server file
+# Set Deno cache directory to persist across requests
+ENV DENO_DIR=/app/.deno_cache
+
+# Create cache directory
+RUN mkdir -p /app/.deno_cache
+
+# Copy files
 COPY server.ts .
+COPY deno.json .
+
+# Pre-cache zod-to-json-schema (used by server.ts)
+RUN deno cache --reload \
+  https://esm.sh/zod-to-json-schema@3.25.0
+
+# Pre-cache common AI SDK dependencies to speed up first loads
+RUN deno cache --reload \
+  https://esm.sh/ai@5.0.83 \
+  https://esm.sh/zod@3.22.0 || true
 
 # Expose port (Railway will set PORT env var)
 EXPOSE 3002
 
 # Run the Deno server
-CMD ["deno", "run", "--allow-net", "--allow-env", "server.ts"]
+CMD ["deno", "run", "--allow-net", "--allow-env", "--allow-read", "--allow-write", "server.ts"]

apps/railway-executor/railway.toml

@@ -0,0 +1,14 @@
+[build]
+builder = "dockerfile"
+dockerfilePath = "Dockerfile"
+
+[deploy]
+startCommand = "deno run --allow-net --allow-env --allow-read --allow-write server.ts"
+restartPolicyType = "on_failure"
+restartPolicyMaxRetries = 10
+
+# Mount persistent volume for Deno cache
+# This persists the cache across deploys and restarts
+[[volumes]]
+mountPath = "/app/.deno_cache"
+name = "deno-cache"

apps/railway-executor/server.ts

@@ -104,7 +104,14 @@ async function loadAndDescribe(req: Request): Promise<Response> {
     } else {
       // Dynamic import from esm.sh (Deno supports this natively!)
       const url = importUrl || `https://esm.sh/${packageName}@${version}`;
-      console.log(`📦 Importing: ${url}`);
+
+      // Log cache status for visibility
+      const isFirstImport = !moduleCache.has(cacheKey);
+      if (isFirstImport) {
+        console.log(`📦 Importing from network (will be cached by Deno): ${url}`);
+      } else {
+        console.log(`✅ Using in-memory cache: ${url}`);
+      }
 
       const module = await import(url);
       let rawExport = module[exportName];