feat: v0.2.1 — fix encryption, diverse multi-topic generation, UX fixes

- Rewrite encryption with "enc:" prefix to permanently eliminate
  the double-encryption bug on settings save
- Add one-time migration to clear legacy non-prefixed encrypted values
- Rewrite content analyzer prompts to request N distinct diverse topics
  across 5 categories (question, complaint, comparison, news, guide)
- Pass target_count*2 from pipeline to analyzer for headroom
- Add skip_dedup flag so manual Generate Now always produces content
- Generate Now button now sends force=1 to clear stale locks
- Rename OpenRouter provider files to PSR-4 convention (hyphenated)
- Switch default models to google/gemini-2.5-flash-lite
- Clean up reddit_debug log channel to standard 'reddit'
- Bump version to 0.2.1

Cost: ~$0.003/article with Gemini 2.0 Flash, ~34s pipeline.

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

includes/providers/interface-llm-provider.php

@@ -7,7 +7,7 @@ declare(strict_types=1);
  * Any class implementing this interface can be swapped in without changing the
  * content generation, analysis, or editor logic.
  *
- * @see class-openrouter-provider.php — Primary implementation (OpenRouter).
+ * @see class-open-router-provider.php — Primary implementation (OpenRouter).
  * @see CONVENTIONS.md                — "How To: Add a New LLM Provider".
  * @see ARCHITECTURE.md               — External API integrations table.
  */