Search sessions (including transcripts) when restoring

[SGudbrandsson]

Problem

When restoring sessions, it is very difficult to find the right one. The current list doesn't give enough signal about what each session contains, so identifying the one to restore is largely guesswork.

Proposal

• Add a search box in the session restore UI.
• Search should match against session metadata (name, project, branch, timestamps).
• Search should also match inside transcripts so I can find a session by something that was said in it.

Acceptance criteria

• Search field visible in the restore flow.
• Matching works across session metadata.
• Matching works across transcript contents.
• Results highlight the matched text / show a snippet of the matching transcript line.