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/middleware-build-manifest.js

@@ -0,0 +1,15 @@
+globalThis.__BUILD_MANIFEST = {
+  "pages": {
+    "/_app": []
+  },
+  "devFiles": [],
+  "polyfillFiles": [],
+  "lowPriorityFiles": [
+    "static/development/_buildManifest.js",
+    "static/development/_ssgManifest.js",
+    "static/development/_clientMiddlewareManifest.js"
+  ],
+  "rootMainFiles": [],
+  "rootMainFilesTree": {},
+  "pagesChunkGroupBootstrapParams": {}
+};