fix: stop .gitignore from excluding build/.next (site 502/blank after deploy)

.gitignore's ".next/" rule (no leading slash) matched at any depth, so
build/.next was silently excluded from every commit even though build.sh
populates it. The Docker image was built without the compiled server/static
output, so server.js had nothing to serve. Anchor the rule to the repo root
and commit the compiled output that Dokploy actually needs.

build/.next/server/app/air-freight.meta

@@ -0,0 +1,17 @@
+{
+  "status": 308,
+  "headers": {
+    "location": "/doormile-wings",
+    "x-nextjs-stale-time": "300",
+    "x-nextjs-prerender": "1",
+    "x-next-cache-tags": "_N_T_/layout,_N_T_/air-freight/layout,_N_T_/air-freight/page,_N_T_/air-freight"
+  },
+  "segmentPaths": [
+    "/_tree",
+    "/_full",
+    "/air-freight/__PAGE__",
+    "/air-freight",
+    "/_index",
+    "/_head"
+  ]
+}