feat(dashboard): per-key model restrictions, pin header routing, combo side-panel picker

- Endpoint: per-API-key model allowlist (schema v3) enforced on chat (403)
  and /v1/models; Full-access toggle + multi-select picker in Keys UI.
- Providers: honor x-connection-id in /v1/chat/completions — pinned requests
  no longer rotate to another account on failure.
- Providers: strategy saves merge into stored enabled:false override;
  Test All groups match grid sections; 1-by-1 skips disabled connections.
- Dashboard: provider-card toggle syncs from server on failure; grid toggles
  always visible; connection rows get clear-✕ for stale error banners.
- Combo editor: on desktop (xl+) the Add-Model picker opens as a floating
  side panel beside the untouched combo popup instead of stacking on top;
  mobile keeps the full-screen overlay.
- Long API-key overflow fixed in key rows + provider model sections.

open-sse/services/accountFallback.js

@@ -26,8 +26,14 @@ export function checkFallbackError(status, errorText, backoffLevel = 0) {
     : "";
 
   for (const rule of ERROR_RULES) {
+    // Request-scoped rule: the request body itself is at fault — no cooldown,
+    // no account lock. Caller must stop rotating and surface the error.
+    if (rule.requestScoped && lowerError && lowerError.includes(rule.text)) {
+      return { shouldFallback: false, requestScoped: true, cooldownMs: 0 };
+    }
+
     // Text-based rule: match substring in error message
-    if (rule.text && lowerError && lowerError.includes(rule.text)) {
+    if (rule.text && !rule.requestScoped && lowerError && lowerError.includes(rule.text)) {
       if (rule.backoff) {
         const newLevel = Math.min(backoffLevel + 1, BACKOFF_CONFIG.maxLevel);
         return { shouldFallback: true, cooldownMs: getQuotaCooldown(newLevel), newBackoffLevel: newLevel };

open-sse/services/compact.js

@@ -1,71 +0,0 @@
-/**
- * Shared combo (model combo) handling with fallback support
- */
-
-/**
- * Get combo models from combos data
- * @param {string} modelStr - Model string to check
- * @param {Array|Object} combosData - Array of combos or object with combos
- * @returns {string[]|null} Array of models or null if not a combo
- */
-export function getComboModelsFromData(modelStr, combosData) {
-  // Don't check if it's in provider/model format
-  if (modelStr.includes("/")) return null;
-  
-  // Handle both array and object formats
-  const combos = Array.isArray(combosData) ? combosData : (combosData?.combos || []);
-  
-  const combo = combos.find(c => c.name === modelStr);
-  if (combo && combo.models && combo.models.length > 0) {
-    return combo.models;
-  }
-  return null;
-}
-
-/**
- * Handle combo chat with fallback
- * @param {Object} options
- * @param {Object} options.body - Request body
- * @param {string[]} options.models - Array of model strings to try
- * @param {Function} options.handleSingleModel - Function to handle single model: (body, modelStr) => Promise<Response>
- * @param {Object} options.log - Logger object
- * @returns {Promise<Response>}
- */
-export async function handleComboChat({ body, models, handleSingleModel, log }) {
-  let lastError = null;
-
-  for (let i = 0; i < models.length; i++) {
-    const modelStr = models[i];
-    log.info("COMBO", `Trying model ${i + 1}/${models.length}: ${modelStr}`);
-
-    let result;
-    try {
-      result = await handleSingleModel(body, modelStr);
-    } catch (e) {
-      lastError = `${modelStr}: ${e.message}`;
-      log.warn("COMBO", `Model threw exception, trying next`, { model: modelStr, error: e.message });
-      continue;
-    }
-
-    // Success or client error - return response
-    if (result.ok || result.status < 500) {
-      return result;
-    }
-
-    // 5xx error - try next model
-    lastError = `${modelStr}: ${result.statusText || result.status}`;
-    log.warn("COMBO", `Model failed, trying next`, { model: modelStr, status: result.status });
-  }
-
-  log.warn("COMBO", "All models failed");
-  
-  // Return 503 with last error
-  return new Response(
-    JSON.stringify({ error: lastError || "All combo models unavailable" }),
-    { 
-      status: 503, 
-      headers: { "Content-Type": "application/json" }
-    }
-  );
-}
-