feat: v0.2.2 — CI hardening, remove dead stubs, strengthen tests

Address CTO audit findings for PRAutoBlogger:
- CI pipeline now runs PHPCS (WordPress standards) and PHPUnit before deploy
- Removed TikTok/Instagram/YouTube stub providers (dead code, not registered)
- Rewrote PublisherTest with real behavioral assertions (post_status, metadata,
  taxonomy, log linking, hooks) instead of method-existence checks
- Added cross-system LLM budget coordination docs to ARCHITECTURE.md
- Bumped version to 0.2.2

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

includes/models/class-source-data.php

@@ -3,7 +3,7 @@ declare(strict_types=1);
 
 /**
  * Value object representing a single piece of collected social media data
- * (a Reddit post, a TikTok comment, etc.).
+ * (e.g., a Reddit post or comment).
  *
  * Triggered by: Source providers create these; Content_Analyzer consumes them.
  * Dependencies: None — pure data object.