refactor(app): DRY pass — split large files, extract shared utils

S1: delete page.new.js (1724L abandoned) + remove dead getAntigravityProjectId
S2: split large files by natural seams
  - usage.js → usage/{github,google,claude,codex,kiro,minimax,misc,shared}.js
  - media-providers page → components/{Embedding,Tts,Generic,Stt}ExampleCard.js
  - EndpointPageClient → endpointConstants.js + endpointPing.js + components/
  - tokenRefresh.js → tokenRefresh/{dedup,providers}.js
  - ProviderLimits/index.js: 16 pure fn + 9 constants → utils.js
  - oauth/providers.js: 7 pure helpers → providerHelpers.js
S3: shared utils
  - getModelKind(m, fallback) → shared/constants/models.js (replaces 20× m.kind||m.type)
  - getStatusVariant → shared/utils/connectionStatus.js (dedup ConnectionRow/ConnectionsCard)
  - sseChunk → open-sse/utils/sse.js (dedup grok-web/perplexity-web)
  - fetchWithTimeout → usage/shared.js (replace 4× AbortController pattern in google.js)
fix: enableObservability2 field name in requestDetailsRepo
Co-authored-by: Cursor <cursoragent@cursor.com>

src/shared/components/ModelSelectModal.js

@@ -4,7 +4,7 @@ import { useState, useMemo, useEffect } from "react";
 import PropTypes from "prop-types";
 import Modal from "./Modal";
 import ProviderIcon from "./ProviderIcon";
-import { getModelsByProviderId } from "@/shared/constants/models";
+import { getModelsByProviderId, getModelKind } from "@/shared/constants/models";
 import { OAUTH_PROVIDERS, APIKEY_PROVIDERS, FREE_PROVIDERS, FREE_TIER_PROVIDERS, AI_PROVIDERS, isOpenAICompatibleProvider, isAnthropicCompatibleProvider, getProviderAlias } from "@/shared/constants/providers";
 
 // Provider order: OAuth first, then Free Tier, then API Key (matches dashboard/providers)
@@ -123,12 +123,11 @@ export default function ModelSelectModal({
     // For these kinds, providers without hardcoded models can still be picked (provider-as-model fallback)
     const ALLOW_PROVIDER_FALLBACK_KINDS = new Set(["tts", "image", "webFetch"]);
 
-    const mKind = (m) => m.kind || m.type;
     // Filter a models[] array by kindFilter (keep only matching kind)
     const filterByKind = (models) => {
-      if (!kindFilter) return models.filter((m) => m.isPlaceholder || !mKind(m) || mKind(m) === "llm");
+      if (!kindFilter) return models.filter((m) => m.isPlaceholder || !getModelKind(m) || getModelKind(m) === "llm");
       if (!TYPED_KINDS.has(kindFilter)) return models;
-      return models.filter((m) => m.isPlaceholder || mKind(m) === kindFilter);
+      return models.filter((m) => m.isPlaceholder || getModelKind(m) === kindFilter);
     };
 
     // Get all active provider IDs from connections (filtered by kindFilter if set)

src/shared/constants/models.js

@@ -36,3 +36,5 @@ export function isValidModel(aliasOrId, modelId) {
 export const AI_MODELS = Object.entries(MODELS).flatMap(([alias, models]) =>
   models.map(m => ({ provider: alias, model: m.id, name: m.name }))
 );
+
+export const getModelKind = (m, fallback = null) => m?.kind || m?.type || fallback;

src/shared/utils/connectionStatus.js

@@ -0,0 +1,6 @@
+export function getStatusVariant(isActive, effectiveStatus) {
+  if (isActive === false) return "default";
+  if (effectiveStatus === "active" || effectiveStatus === "success") return "success";
+  if (effectiveStatus === "error" || effectiveStatus === "expired" || effectiveStatus === "unavailable") return "error";
+  return "default";
+}