fix(app): sort session list by updated time instead of id

[education-01]

Summary

• Fix session list sorting to use time.updated (with time.created fallback) instead of id
• Change two sort comparators in global-sync.tsx and session-trim.ts

Why

Fixes #17474 - Session list was sorted by id, making the order appear random.

Changes

• packages/app/src/context/global-sync.tsx: Use (b.time.updated ?? b.time.created) - (a.time.updated ?? a.time.created) for sorting
• packages/app/src/context/global-sync/session-trim.ts: Use existing compareSessionRecent() function for sorting

The compareSessionRecent helper already implements correct recency ordering with id tiebreaker.

[github-actions]

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[github-actions]

The following comment was made by an LLM, it may be inaccurate:

I found two related/duplicate PRs addressing the same session sorting issue:

1. PR [FIX] session list should be sorted by updated time, not id #17524 - [FIX] session list should be sorted by updated time, not id

   • [FIX] session list should be sorted by updated time, not id #17524
   • Appears to be the same fix for session list sorting

2. PR fix(app): session listing sorted by update time rather than id #17475 - fix(app): session listing sorted by update time rather than id

   • fix(app): session listing sorted by update time rather than id #17475
   • Also addresses the same session sorting issue

Both PRs are addressing the same core issue: sorting sessions by updated time instead of ID, which is exactly what PR #17526 (the current PR) is attempting to fix. These are likely duplicates or related attempts to solve issue #17474.