Fix podcasts generating in English + failing with invalid JSON

Two root causes, both fixed in the bind-mounted podcast prompt templates
(prompts/podcast/*.jinja):

1. Language: the episode profile's `language` field IS passed to both
   podcast_creator templates as {{ language }}, but the stock templates never
   reference it — so podcasts came out English (driven only by the English
   stock briefings/speakers), then read aloud by the German-locked Chatterbox
   TTS = "English with a German accent". Added a CRITICAL LANGUAGE REQUIREMENT
   block keyed on {{ language }} to both templates; now `language: "de"`
   actually forces German. Verified end-to-end: a full run produced a 44-line
   all-German transcript + audio.

2. Invalid json output failures: qwen3.5:27b is a thinking model; on long
   segments the <think> block ate the response-token budget and truncated the
   JSON. Prepended /no_think to both templates (~3x faster, valid JSON).

Templates are bind-mounted read-only via docker-compose (directory mount, so
edits survive a container restart without inode-staleness). Bundled briefings
and speaker backstories were also translated to German to reduce drift.

Known limitation documented: feeding an entire book (~70k tokens) as podcast
content makes each of the 6 LLM calls take ~3.5 min and is unreliable; use a
shorter source or summary. Confirmed working with concise content.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docker-compose.yml

@@ -34,3 +34,11 @@ services:
       - "host.docker.internal:host-gateway"
     volumes:
       - ./notebook_data:/app/data
+      # Podcast-Prompt-Vorlagen mit expliziter Sprachanweisung ({{ language }})
+      # und abgeschaltetem Thinking-Modus (/no_think), damit Podcasts in der
+      # eingestellten Sprache erzeugt werden (statt Englisch) und das JSON bei
+      # langen Segmenten nicht durch riesige Reasoning-Blöcke abgeschnitten wird.
+      # Verzeichnis-Mount (nicht Einzeldateien), damit Edits ohne Inode-Probleme
+      # nach einem Container-Neustart greifen. Der Ordner im Image enthält nur
+      # genau diese zwei Vorlagen.
+      - ./prompts/podcast:/app/prompts/podcast:ro