TTS fixes, Inworld improvements, footer redesign, episodes 15-25, invoice script fix

- Fix TTS text pipeline: new caps handling (spell out unknown acronyms, lowercase
  emphasis words), action-word lookahead for parenthetical stripping, abbreviation
  expansions (US→United States, NM→New Mexico), pronunciation fixes
- Inworld TTS: camelCase API fields, speakingRate per-voice overrides, retry logic
  with exponential backoff (3 attempts)
- Footer redesign: SVG icons for social/podcast links across all pages
- Stats page: show "Rate us on Spotify" instead of "not public" placeholder
- New voices, expanded caller prompts and problem scenarios
- Social posting via Postiz, YouTube upload in publish pipeline
- Episode transcripts 15-25, terms page, sitemap updates
- Fix invoice script: match Timing totals using merged Task+App intervals

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

backend/services/llm.py

@@ -155,11 +155,11 @@ class LLMService:
                 json={
                     "model": model,
                     "messages": messages,
-                    "max_tokens": max_tokens or 300,
-                    "temperature": 0.8,
-                    "top_p": 0.92,
-                    "frequency_penalty": 0.5,
-                    "presence_penalty": 0.3,
+                    "max_tokens": max_tokens or 500,
+                    "temperature": 0.65,
+                    "top_p": 0.9,
+                    "frequency_penalty": 0.3,
+                    "presence_penalty": 0.15,
                 },
                 timeout=timeout,
             )