Implement usage tracking and limits enforcement

- Fix get_usage() to count from user_episodes table instead of
episodes.user_id
  - Now correctly tracks when episodes are added to user's feed -
  Handles shared/existing episodes properly (count against the user
  who added them)
- Add comprehensive test suite for usage limits (TestUsageLimits):
  - test_usage_counts_episodes_added_to_feed -
  test_usage_counts_existing_episodes_correctly -
  test_free_tier_limit_enforcement (10 articles) -
  test_can_submit_blocks_at_limit - test_paid_tier_unlimited
- Billing.can_submit() now properly enforces 10 article limit
for free tier - Usage tracking via user_episodes.added_at ensures
accurate billing

Completes t-144eKR1

1 files changed, 1 insertions, 1 deletions

diff --git a/.tasks/tasks.jsonl b/.tasks/tasks.jsonl
index f505eff..7246da0 100644
--- a/.tasks/tasks.jsonl
+++ b/.tasks/tasks.jsonl
@@ -26,7 +26,7 @@
 {"taskCreatedAt":"2025-11-09T16:48:40.260201423Z","taskDependencies":[],"taskId":"t-143KQl2","taskNamespace":"Biz/PodcastItLater.hs","taskParent":null,"taskStatus":"Open","taskTitle":"PodcastItLater: Path to Paid Product","taskType":"Epic","taskUpdatedAt":"2025-11-09T16:48:40.260201423Z"}
 {"taskCreatedAt":"2025-11-09T16:48:47.076581674Z","taskDependencies":[],"taskId":"t-144drAE","taskNamespace":"Biz/PodcastItLater.hs","taskParent":"t-143KQl2","taskStatus":"Done","taskTitle":"Adopt Bootstrap CSS for UI improvements","taskType":"WorkTask","taskUpdatedAt":"2025-11-09T17:00:05.424532832Z"}
 {"taskCreatedAt":"2025-11-09T16:48:47.237113366Z","taskDependencies":[],"taskId":"t-144e7lF","taskNamespace":"Biz/PodcastItLater.hs","taskParent":"t-143KQl2","taskStatus":"Done","taskTitle":"Add Stripe integration for billing","taskType":"WorkTask","taskUpdatedAt":"2025-11-09T23:04:23.856763018Z"}
-{"taskCreatedAt":"2025-11-09T16:48:47.388960509Z","taskDependencies":[],"taskId":"t-144eKR1","taskNamespace":"Biz/PodcastItLater.hs","taskParent":"t-143KQl2","taskStatus":"Open","taskTitle":"Implement usage tracking and limits","taskType":"WorkTask","taskUpdatedAt":"2025-11-09T16:48:47.388960509Z"}
+{"taskCreatedAt":"2025-11-09T16:48:47.388960509Z","taskDependencies":[],"taskId":"t-144eKR1","taskNamespace":"Biz/PodcastItLater.hs","taskParent":"t-143KQl2","taskStatus":"Done","taskTitle":"Implement usage tracking and limits","taskType":"WorkTask","taskUpdatedAt":"2025-11-19T03:27:25.707745105Z"}
 {"taskCreatedAt":"2025-11-09T16:48:47.589181852Z","taskDependencies":[],"taskId":"t-144fAWn","taskNamespace":"Biz/PodcastItLater.hs","taskParent":"t-143KQl2","taskStatus":"Done","taskTitle":"Add email notifications (transactional)","taskType":"WorkTask","taskUpdatedAt":"2025-11-13T01:35:54.519545888Z"}
 {"taskCreatedAt":"2025-11-09T16:48:47.737218185Z","taskDependencies":[],"taskId":"t-144gds4","taskNamespace":"Biz/PodcastItLater.hs","taskParent":"t-143KQl2","taskStatus":"Done","taskTitle":"Migrate from SQLite to PostgreSQL","taskType":"WorkTask","taskUpdatedAt":"2025-11-13T01:35:54.70061831Z"}
 {"taskCreatedAt":"2025-11-09T16:48:47.887102357Z","taskDependencies":[],"taskId":"t-144gQry","taskNamespace":"Biz/PodcastItLater.hs","taskParent":"t-143KQl2","taskStatus":"Open","taskTitle":"Create basic admin dashboard","taskType":"WorkTask","taskUpdatedAt":"2025-11-09T16:48:47.887102357Z"}