fix(desktop): reduce active meeting note lag

[ComputelessComputer]

Limit session persister writes to the artifacts changed by each TinyBase transaction and avoid parsing transcripts from unchanged sessions.

---

Note

Medium Risk
Changes the session persistence decision logic to skip writing some artifacts based on TinyBase change sets; mistakes here could cause sessions, transcripts, or notes to not be saved/updated in some edge cases (especially around tag/folder updates).

Overview
Reduces session persister work by computing a per-transaction SessionSaveScope and only generating save operations for the artifacts actually affected (session metadata, transcript.json, and/or note output), instead of always writing all three.

Improves change detection by expanding getChangedSessionIds to account for tag-driven session impacts (via mapping_tag_session and direct tags changes), and updates transcript saving to only parse/group transcripts for changedSessionIds to avoid touching unchanged sessions; adds focused tests for the new scoping and transcript filtering behavior.

^{Reviewed by Cursor Bugbot for commit d14142c. Bugbot is set up for automated code reviews on this repo. Configure here.}

[netlify]

✅ Deploy Preview for old-char canceled.

Name	Link
🔨 Latest commit	d14142c
🔍 Latest deploy log	https://app.netlify.com/projects/old-char/deploys/6a05f72949127b0008fdf443