[Devathmaj]

Description

Adds Kodexis Reddit API provider as a fallback when REDDIT_INGESTION_ENABLED=false. The Kodexis API fetches the latest posts (using sort=new filter) from configured subreddits, with built-in filtering to exclude exam/certification passed posts while preserving voucher-related terms like free exam and exam voucher.

Also removes the deprecated mcsa subreddit from the catalog.

Type of Change

• New feature
• New source
• Configuration / settings change
• Documentation update

Affected Components

• Scheduler / Dispatcher
• Reddit Integration
• Configuration / Settings

Testing

• Ran pytest - all tests pass (52 passed, 15 skipped)
• Ran ruff check . && ruff format . - no lint errors
• Verified Kodexis API integration works with live API calls (tested AWSCertifications, AzureCertification, CompTIA)
• Verified exam/certification + pass filter logic with unit tests
• Verified fallback chain: OAuth -> Kodexis -> RSS

Migration

• This PR includes an Alembic migration (not applicable)

Policy Checklist

• This PR touches one or more policy-sensitive files (scheduler.py, reddit/collector.py)

If checked, confirm all of the following:

• robots.txt compliance is preserved - Kodexis API is a third-party service, no direct scraping
• No default crawl delays have been reduced below 2.0 seconds
• Reddit rate limits and Responsible Builder Policy are respected (Kodexis handles this server-side)
• REDDIT_INGESTION_ENABLED=false still collects Reddit - now via Kodexis API instead of RSS, with RSS as final fallback
• No new direct httpx or aiohttp calls exist outside the policy layer - Kodexis client uses the standard policy layer via scheduler

Explanation:
The Kodexis API is a third-party Reddit data provider that respects Reddits API terms. When REDDIT_INGESTION_ENABLED=false, the system now uses Kodexis (if API key configured) as a more reliable alternative to RSS feeds, with RSS as the final fallback. The exam/certification + pass filter reduces noise from self-promotional I passed! posts while preserving voucher signals.

Additional Notes

Files Added

• voucherbot/providers/Kodexis/client.py - KodexisRedditClient
• voucherbot/providers/Kodexis/init.py - Module export

Files Modified

• .env.example - Added KODEXIS_API_KEY config
• voucherbot/config/settings.py - Added kodexis_api_key setting
• voucherbot/providers/reddit/collector.py - Kodexis fallback + exam/cert + pass filter
• voucherbot/services/scheduler.py - Initialize Kodexis client and pass to collector
• voucherbot/database/bootstrap.py - Removed mcsa subreddit
• sources/Subreddit.txt - Removed mcsa from documentation

Fallback Chain

1. OAuth API (REDDIT_INGESTION_ENABLED=true + credentials) -> asyncpraw
2. Kodexis API (REDDIT_INGESTION_ENABLED=false + KODEXIS_API_KEY) -> sort=new filter
3. RSS (no Kodexis key or Kodexis fails) -> public Reddit RSS feeds

Exam/Certification + Pass Filter

Blocks posts containing standalone exam or certification + pass/passed/passing, with exclusions for:

• free exam, exam voucher, exam credit, beta exam, retake
• free certification, certification voucher

This preserves voucher signals while filtering out I passed my exam! self-reports.