Saved-session refresh reconciles the full catalog per streamed item

[VincentBailly]

When the saved-session view refreshes, it streams items one at a time, and for each one it runs a full catalog reconciliation. As the saved-session catalog grows, that repeated per-item work scales badly: the same reconciliation logic runs again and again instead of once for the batch.

The fix I'm proposing is small: throttle progressive updates during the refresh to a bounded 100 ms window, without resetting the timer for each new item that arrives inside that window. The final result still goes through immediate, full reconciliation, so the authoritative payload and the daemon/catalog protocol don't change at all. This only affects how often the intermediate UI updates happen while streaming.

The change touches exactly two files: the source file with the throttling logic, and its test file.

Validation:

• Focused regression: 21/21 passing
• Related tests: 127/127 passing
• Expanded safe unit set: 432/432 passing
• Project check: passed
• Offline-equivalent package build: passed

An independent review also looked at this and approved the direction.

I opened PR #1800 (#1800) with the implementation, but it was automatically closed by the contribution gate. Per CONTRIBUTING.md, public contributions are supposed to start here in Discussions, so I'm posting this to get maintainer feedback on the approach before going further.

Happy to share more detail on the implementation if useful.

[awhite0030]

Investigated this report and produced a candidate fix, validated on a fork of this repository.

Root cause, fix and validation from the working notes:

Root cause: The agents view streamed saved-session updates and immediately reconciled the full catalog per item, which scales poorly as the saved-session catalog grows.
Fix: Throttled progressive updates during the refresh to a bounded 100 ms window, without resetting the timer for each new item that arrives inside that window. The timer is properly cleared upon final settlement of the request.
Validation:

• Focused regression: 31/31 passing tests in packages/coding-agent/test/agents-view-mode.test.ts
• Project check: passed

Upstream discussion: #1801

Diff: awhite0030/prime-agent@main...fix-throttle-saved-session-updates-372602986612314753
Full pull request: awhite0030#22

The change passes npm run check and the focused regression tests against current main. If a fix for this is still wanted, I can open a pull request.