feat: Ollama Cloud quota tracker + proactive background OAuth refresh

Ollama: replace informational stub with real quota tracker hitting ollama.com/api/usage (session 5h + weekly 7d, 0..1 ratio) and /api/me plan label; bind handler to apiKey + add features.usageApikey so apikey connections work.

Token refresh: add backgroundTokenRefresh scheduler that refreshes OAuth connections within max(provider lead, 30min) of expiry, independent of inbound traffic (10s after boot, then every 5min, unref'd timers, DISABLE_BACKGROUND_TOKEN_REFRESH kill-switch, fail-open per tick/connection). Registered from custom-server.js (listening) and initializeApp.js. checkAndRefreshToken gains opt-in {force} for the scheduler; request path unchanged.

open-sse/providers/registry/ollama.js

@@ -32,5 +32,6 @@ export default {
   serviceKinds: ["llm"],
   features: {
     usage: true,
+    usageApikey: true,
   },
 };