Scheduled tasks fail with 'API Error: Rate limit reached' even with available quota

Description

Scheduled tasks consistently fail with API Error: Rate limit reached — both manual runs and automatic cron-triggered runs.

Environment

• Claude Code CLI (Mac, darwin)
• Paid plan with available usage quota
• 3 scheduled tasks configured with well-separated cron times

Steps to Reproduce

1. Create multiple scheduled tasks with different cron schedules (e.g., 07:58, 14:23, 23:03)
2. Click "Run" on any single task
3. Immediately get API Error: Rate limit reached
4. Wait for automatic cron execution — tasks also fail silently (lastRunAt does not update)

Expected Behavior

• Manual run should execute the task
• Automatic cron runs should fire at scheduled times

Actual Behavior

• Manual run immediately returns API Error: Rate limit reached
• Automatic cron runs do not execute at all (lastRunAt stuck at the same timestamp)
• This persists even when API usage quota is clearly not exhausted

Task Configuration

auto-daily-build:  cron "3 23 * * *"   — lastRunAt: 2026-03-30T20:08:33Z
traffic-monitor:   cron "57 7 * * *"   — lastRunAt: 2026-03-30T20:08:21Z  
reddit-promote:    cron "23 14 * * *"  — lastRunAt: 2026-03-30T20:08:08Z

All three have enabled: true but none have run since 2026-03-30 ~20:08 UTC. Scheduled runs on 2026-03-31 were all skipped.

Impact

Paying user unable to use scheduled tasks feature at all — neither manual nor automatic execution works.