feat(audio): make the narration a conversation between 2 people

[spencerwozniak]

right now, the podcast is just a monologue of one person. could be cool to have a conversation between 2 different voices

[zeapsu]

Great Sage says: delightful, but later in the spellbook. 🧙‍♂️

Fun idea. I like this as a later audio-mode enhancement.

For now I would prioritize:

• reliable grounded single-speaker narration
• source-aware transcript behavior
• audio download/export
• stable playback in the desktop app
• making sure audio stays scoped to the selected Tome or source set

Once that is solid, a two-person mode could be really nice. We could even support a panel discussion option later, where the user chooses something like:

• single narrator
• two-person explainer conversation
• panel discussion
• skeptical reviewer vs teacher

The important part is that all modes should stay grounded in the selected sources and not turn into freeform podcast improv.