diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..7777069
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,34 @@
+# Minimal CI floor: lint + typecheck (npm run verify) and a production build.
+# Purpose is to stop the repo silently rotting — not to run a test suite.
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  verify:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+
+      - run: npm ci
+
+      # Lint + typecheck.
+      - run: npm run verify
+
+      # Production build. The build statically prerenders pages that construct a
+      # Supabase browser client, so it needs the two NEXT_PUBLIC_ values to be
+      # PRESENT (non-empty) — no live database or real secret is required. These
+      # are deliberately fake placeholders, safe to commit (the anon key is a
+      # public client value by design).
+      - run: npm run build
+        env:
+          NEXT_PUBLIC_SUPABASE_URL: https://placeholder.supabase.co
+          NEXT_PUBLIC_SUPABASE_ANON_KEY: placeholder-anon-key-ci-build-only
diff --git a/package.json b/package.json
index 710aeaa..ec05aa3 100644
--- a/package.json
+++ b/package.json
@@ -6,7 +6,9 @@
     "dev": "next dev",
     "build": "next build",
     "start": "next start",
-    "lint": "eslint"
+    "lint": "eslint",
+    "typecheck": "tsc --noEmit",
+    "verify": "npm run lint && npm run typecheck"
   },
   "dependencies": {
     "@base-ui/react": "^1.3.0",
diff --git a/src/app/project/[id]/surface/page.tsx b/src/app/project/[id]/surface/page.tsx
index f2f0684..8c91f81 100644
--- a/src/app/project/[id]/surface/page.tsx
+++ b/src/app/project/[id]/surface/page.tsx
@@ -1,6 +1,6 @@
 'use client'
 
-import { use, useState, useEffect } from 'react'
+import { use, useState } from 'react'
 import { useSurface, useUpsertSurface } from '@/hooks/useSurface'
 import { SURFACE_PRESETS, type SurfacePreset } from '@/lib/config/surface-presets'
 import { getTotalDimensions, getSeamPositionsFromPanels } from '@/lib/domain/surface'
@@ -27,15 +27,18 @@ export default function SurfacePage({ params }: { params: Promise<{ id: string }
   const [dpiTarget, setDpiTarget] = useState(200)
   const [bleedMm, setBleedMm] = useState(3)
 
-  useEffect(() => {
-    if (existingSurface) {
-      setPanels(existingSurface.panels)
-      setDeadZones(existingSurface.dead_zones)
-      setDpiTarget(existingSurface.dpi_target)
-      setBleedMm(existingSurface.bleed_mm)
-      setSurfaceType(existingSurface.type)
-    }
-  }, [existingSurface])
+  // Hydrate the form once the saved surface loads. Adjusting state during render
+  // against a remembered previous value (React "you might not need an effect")
+  // avoids the extra render pass an effect-driven setState would cause.
+  const [hydratedSurface, setHydratedSurface] = useState(existingSurface)
+  if (existingSurface && existingSurface !== hydratedSurface) {
+    setHydratedSurface(existingSurface)
+    setPanels(existingSurface.panels)
+    setDeadZones(existingSurface.dead_zones)
+    setDpiTarget(existingSurface.dpi_target)
+    setBleedMm(existingSurface.bleed_mm)
+    setSurfaceType(existingSurface.type)
+  }
 
   function applyPreset(preset: SurfacePreset) {
     setSelectedPreset(preset.id)
diff --git a/src/components/layout/AppShell.tsx b/src/components/layout/AppShell.tsx
index 90dd61e..a63f033 100644
--- a/src/components/layout/AppShell.tsx
+++ b/src/components/layout/AppShell.tsx
@@ -32,10 +32,14 @@ export function AppShell({ children }: { children: ReactNode }) {
     return () => window.removeEventListener('scroll', onScroll)
   }, [])
 
-  // Close mobile menu on route change
-  useEffect(() => {
+  // Close the mobile menu on route change. Adjusting state during render with a
+  // remembered previous value (React "you might not need an effect") avoids the
+  // cascading re-render an effect-driven setState would trigger.
+  const [prevPathname, setPrevPathname] = useState(pathname)
+  if (pathname !== prevPathname) {
+    setPrevPathname(pathname)
     setMobileMenuOpen(false)
-  }, [pathname])
+  }
 
   // Prevent body scroll when mobile menu is open
   useEffect(() => {
diff --git a/tsconfig.json b/tsconfig.json
index cf9c65d..c67d202 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -30,5 +30,5 @@
     ".next/dev/types/**/*.ts",
     "**/*.mts"
   ],
-  "exclude": ["node_modules"]
+  "exclude": ["node_modules", "app", "_archive"]
 }