fix: escalate to model fallback after rate-limit profile rotation cap (#58707)

* fix: escalate to model fallback after rate-limit profile rotation cap

Per-model rate limits (e.g. Anthropic Sonnet-only quotas) are not
relieved by rotating auth profiles — if all profiles share the same
model quota, cycling between them loops forever without falling back
to the next model in the configured fallbacks chain.

Apply the same rotation-cap pattern introduced for overloaded_error
(#58348) to rate_limit errors:

- Add `rateLimitedProfileRotations` to auth.cooldowns config (default: 1)
- After N profile rotations on a rate_limit error, throw FailoverError
  to trigger cross-provider model fallback
- Add `resolveRateLimitProfileRotationLimit` helper following the same
  pattern as `resolveOverloadProfileRotationLimit`

Fixes #58572

* fix: cap prompt-side rate-limit failover (#58707) (thanks @Forgely3D)

* fix: restore latest-main gates for #58707

---------

Co-authored-by: Ember (Forgely3D) <ember@forgely.co>
Co-authored-by: Peter Steinberger <steipete@gmail.com>

docs/.generated/config-baseline.json

@@ -7907,6 +7907,23 @@
       "help": "Maximum same-provider auth-profile rotations allowed for overloaded errors before switching to model fallback (default: 1).",
       "hasChildren": false
     },
+    {
+      "path": "auth.cooldowns.rateLimitedProfileRotations",
+      "kind": "core",
+      "type": "integer",
+      "required": false,
+      "deprecated": false,
+      "sensitive": false,
+      "tags": [
+        "access",
+        "auth",
+        "performance",
+        "storage"
+      ],
+      "label": "Rate-Limited Profile Rotations",
+      "help": "Maximum same-provider auth-profile rotations allowed for rate-limit errors before switching to model fallback (default: 1).",
+      "hasChildren": false
+    },
     {
       "path": "auth.order",
       "kind": "core",

docs/.generated/config-baseline.jsonl

@@ -1,4 +1,4 @@
-{"generatedBy":"scripts/generate-config-doc-baseline.ts","recordType":"meta","totalPaths":5729}
+{"generatedBy":"scripts/generate-config-doc-baseline.ts","recordType":"meta","totalPaths":5730}
 {"recordType":"path","path":"acp","kind":"core","type":"object","required":false,"deprecated":false,"sensitive":false,"tags":["advanced"],"label":"ACP","help":"ACP runtime controls for enabling dispatch, selecting backends, constraining allowed agent targets, and tuning streamed turn projection behavior.","hasChildren":true}
 {"recordType":"path","path":"acp.allowedAgents","kind":"core","type":"array","required":false,"deprecated":false,"sensitive":false,"tags":["access"],"label":"ACP Allowed Agents","help":"Allowlist of ACP target agent ids permitted for ACP runtime sessions. Empty means no additional allowlist restriction.","hasChildren":true}
 {"recordType":"path","path":"acp.allowedAgents.*","kind":"core","type":"string","required":false,"deprecated":false,"sensitive":false,"tags":[],"hasChildren":false}
@@ -701,6 +701,7 @@
 {"recordType":"path","path":"auth.cooldowns.failureWindowHours","kind":"core","type":"number","required":false,"deprecated":false,"sensitive":false,"tags":["access","auth"],"label":"Failover Window (hours)","help":"Failure window (hours) for backoff counters (default: 24).","hasChildren":false}
 {"recordType":"path","path":"auth.cooldowns.overloadedBackoffMs","kind":"core","type":"integer","required":false,"deprecated":false,"sensitive":false,"tags":["access","auth","reliability","storage"],"label":"Overloaded Backoff (ms)","help":"Fixed delay in milliseconds before retrying an overloaded provider/profile rotation (default: 0).","hasChildren":false}
 {"recordType":"path","path":"auth.cooldowns.overloadedProfileRotations","kind":"core","type":"integer","required":false,"deprecated":false,"sensitive":false,"tags":["access","auth","storage"],"label":"Overloaded Profile Rotations","help":"Maximum same-provider auth-profile rotations allowed for overloaded errors before switching to model fallback (default: 1).","hasChildren":false}
+{"recordType":"path","path":"auth.cooldowns.rateLimitedProfileRotations","kind":"core","type":"integer","required":false,"deprecated":false,"sensitive":false,"tags":["access","auth","performance","storage"],"label":"Rate-Limited Profile Rotations","help":"Maximum same-provider auth-profile rotations allowed for rate-limit errors before switching to model fallback (default: 1).","hasChildren":false}
 {"recordType":"path","path":"auth.order","kind":"core","type":"object","required":false,"deprecated":false,"sensitive":false,"tags":["access","auth"],"label":"Auth Profile Order","help":"Ordered auth profile IDs per provider (used for automatic failover).","hasChildren":true}
 {"recordType":"path","path":"auth.order.*","kind":"core","type":"array","required":false,"deprecated":false,"sensitive":false,"tags":[],"hasChildren":true}
 {"recordType":"path","path":"auth.order.*.*","kind":"core","type":"string","required":false,"deprecated":false,"sensitive":false,"tags":[],"hasChildren":false}