Resume parked work when a provider's monthly limit is raised

The heartbeat scheduler enqueued runs even while a provider's monthly
usage window was full, so every task burned its 3-attempt retry budget
on instant quota failures within seconds and stayed dead forever -
raising the limit (or restarting) never revived anything.

- Park tasks (skip enqueue) while their provider is at its
  monthly_request_limit instead of creating runs doomed to fail
- Exclude quota-blocked failures from the 3-attempt retry budget,
  retroactively reviving tasks abandoned by past filled windows
- Share the gate message as PROVIDER_MONTHLY_LIMIT_MESSAGE and log
  quota-block transitions once per state change for diagnosability
- Ignore landing/ (self-contained Next.js sub-project) and
  built-in skills/ (prompt content) in eslint so verify:ci lints only
  application code

src/main/services/provider-background-service.ts

@@ -9,7 +9,7 @@ import {
   type ProviderAuthType,
   type ProviderExecutionMode,
 } from "../../shared/domain";
-import { currentProviderUsageWindow, type ProviderObservedRateLimitState } from "../../shared/provider-runtime-domain";
+import { currentProviderUsageWindow, PROVIDER_MONTHLY_LIMIT_MESSAGE, type ProviderObservedRateLimitState } from "../../shared/provider-runtime-domain";
 import { AuditService } from "./audit-service";
 import { AuthBrokerService, type ProviderSecretVault } from "./auth-broker-service";
 import { OperationsService } from "./operations-service";
@@ -238,7 +238,7 @@ export class ProviderBackgroundService {
       where org_id = ? and provider_id = ? and window_start = ?
     `).get(orgId, provider.id, window.start) as { request_count: number } | undefined;
     const requestCount = usage?.request_count ?? 0;
-    if (requestCount >= provider.monthly_request_limit) throw new Error("Provider monthly request limit has been reached.");
+    if (requestCount >= provider.monthly_request_limit) throw new Error(PROVIDER_MONTHLY_LIMIT_MESSAGE);
   }
 
   private normalizeWorkspaceId(orgId: string, workspaceId: string | null): string | null {