Changes

PR #1832 by ksylvan: Improve channel management in Gemini provider

• Fix: improve channel management in Gemini streaming method
• Add deferred channel close at function start
• Return error immediately instead of breaking loop
• Remove redundant channel close statements from loop
• Ensure channel closes on all exit paths consistently

PR #1831 by ksylvan: Remove get_youtube_rss pattern

• Chore: remove get_youtube_rss pattern from multiple files
• Remove get_youtube_rss from pattern_explanations.md
• Delete get_youtube_rss entry in pattern_descriptions.json
• Delete get_youtube_rss entry in pattern_extracts.json
• Remove get_youtube_rss from suggest_pattern/system.md