fix(db): add missing apiKeys columns + restore ApiExplorerModal export

- schema.js: add createdAt/allowedModels to apiKeys, bump SCHEMA_VERSION 3->4
- shared/components/index.js: restore ApiExplorerModal barrel export (was replaced by TagInput)
- combos: tag support, repo + api + page updates

tmp/9r-smoke-dist/dev/server/instrumentation/middleware-manifest.json

@@ -0,0 +1,12 @@
+{
+  "sorted_middleware": [],
+  "middleware": {},
+  "instrumentation": {
+    "files": [
+      "server/edge/chunks/_06oe804._.js",
+      "server/edge/chunks/turbopack-node_modules_next_dist_esm_build_templates_edge-wrapper_0xnf3d4.js"
+    ],
+    "name": "instrumentation"
+  },
+  "functions": {}
+}