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/regulars.py

@@ -51,7 +51,8 @@ class RegularCallerService:
 
     def add_regular(self, name: str, gender: str, age: int, job: str,
                     location: str, personality_traits: list[str],
-                    first_call_summary: str, voice: str = None) -> dict:
+                    first_call_summary: str, voice: str = None,
+                    stable_seeds: dict = None) -> dict:
         """Promote a first-time caller to regular"""
         # Retire oldest if at cap
         if len(self._regulars) >= MAX_REGULARS:
@@ -68,6 +69,7 @@ class RegularCallerService:
             "location": location,
             "personality_traits": personality_traits,
             "voice": voice,
+            "stable_seeds": stable_seeds or {},
             "call_history": [
                 {"summary": first_call_summary, "timestamp": time.time()}
             ],