Selective fixes from PR #35: Model-specific rate limits & robustness improvements (#37)

* feat: apply local user changes and fixes

* ;D

* Implement OpenAI support, model-specific rate limiting, and robustness fixes

* docs: update pr title

* feat: ensure unique openai models endpoint

* fix: startup banner alignment and removed duplicates

* feat: add model fallback system with --fallback flag

* fix: accounts cli hanging after completion

* feat: add exit option to accounts cli menu

* fix: remove circular dependency warning for fallback flag

* feat: show active modes in banner and hide their flags

* Remove OpenAI compatibility and fallback features from PR #35

Cherry-picked selective fixes from PR #35 while removing:
- OpenAI-compatible API endpoints (/openai/v1/*)
- Model fallback system (fallback-config.js)
- Thinking block skip for Gemini models
- Unnecessary files (pullrequest.md, test-fix.js, test-openai.js)

Retained improvements:
- Network error handling with retry logic
- Model-specific rate limiting
- Enhanced health check with quota info
- CLI fixes (exit option, process.exit)
- Startup banner alignment (debug mode only)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* banner alignment fix

* Refactor: Model-specific rate limits and cleanup deprecated code

- Remove global rate limit fields (isRateLimited, rateLimitResetTime) in favor of model-specific limits (modelRateLimits[modelId])
- Remove deprecated wrapper functions (is429Error, isAuthInvalidError) from handlers
- Filter fetchAvailableModels to only return Claude and Gemini models
- Fix getCurrentStickyAccount() to pass model param after waiting
- Update /account-limits endpoint to show model-specific limits
- Remove multi-account OAuth flow to avoid state mismatch errors

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* fix: show (x/y) limited status in account-limits table

- Status is now "ok" only when all models are available
- Shows "(x/y) limited" when x out of y models are exhausted
- Provides better visibility into partial rate limiting

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* docs: update CLAUDE.md with model-specific rate limiting

- Document modelRateLimits[modelId] for per-model rate tracking
- Add isNetworkError() helper to utilities section

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

---------

Co-authored-by: M1noa <minoa@minoa.cat>
Co-authored-by: Minoa <altgithub@minoa.cat>
Co-authored-by: Claude <noreply@anthropic.com>

src/cloudcode/model-api.js

@@ -4,9 +4,19 @@
  * Handles model listing and quota retrieval from the Cloud Code API.
  */
 
-import { ANTIGRAVITY_ENDPOINT_FALLBACKS, ANTIGRAVITY_HEADERS } from '../constants.js';
+import { ANTIGRAVITY_ENDPOINT_FALLBACKS, ANTIGRAVITY_HEADERS, getModelFamily } from '../constants.js';
 import { logger } from '../utils/logger.js';
 
+/**
+ * Check if a model is supported (Claude or Gemini)
+ * @param {string} modelId - Model ID to check
+ * @returns {boolean} True if model is supported
+ */
+function isSupportedModel(modelId) {
+    const family = getModelFamily(modelId);
+    return family === 'claude' || family === 'gemini';
+}
+
 /**
  * List available models in Anthropic API format
  * Fetches models dynamically from the Cloud Code API
@@ -20,7 +30,9 @@ export async function listModels(token) {
         return { object: 'list', data: [] };
     }
 
-    const modelList = Object.entries(data.models).map(([modelId, modelData]) => ({
+    const modelList = Object.entries(data.models)
+        .filter(([modelId]) => isSupportedModel(modelId))
+        .map(([modelId, modelData]) => ({
         id: modelId,
         object: 'model',
         created: Math.floor(Date.now() / 1000),
@@ -85,6 +97,9 @@ export async function getModelQuotas(token) {
 
     const quotas = {};
     for (const [modelId, modelData] of Object.entries(data.models)) {
+        // Only include Claude and Gemini models
+        if (!isSupportedModel(modelId)) continue;
+
         if (modelData.quotaInfo) {
             quotas[modelId] = {
                 remainingFraction: modelData.quotaInfo.remainingFraction ?? null,