fix(desktop): refresh active sessions from external updates

[joelbrilliant]

Summary

• Adds a guarded Hermes Desktop read-repair loop for the selected stored session.
• Refreshes active session messages when another client/gateway, such as Telegram on phone, writes to the same session while Desktop is open.
• Skips refresh while the active run is busy or awaiting a response so polling cannot overwrite local optimistic/in-flight messages.
• Refreshes the sidebar session list only when the persisted session revision actually changes.

Why

Hermes Desktop remote mode can show gateway-origin messages after a manual renderer refresh, but the active session view does not currently notice those persisted changes while the app stays open. This removes the need for Cmd+R in the common “chat on phone, watch on Desktop” workflow.

Test plan

• CI=1 npx vitest run --environment jsdom src/app/session/hooks/use-external-session-refresh.test.ts
• npx eslint src/app/session/hooks/use-external-session-refresh.ts src/app/session/hooks/use-external-session-refresh.test.ts src/app/desktop-controller.tsx
• npm run type-check
• npm run build

Review notes

A first review found a race where a poll could start while idle, then overwrite an optimistic/in-flight prompt if the session became busy before the persisted read returned. The final implementation rechecks runtime session state after the awaited read and includes a regression test for that race.

[tonydwb]

Code Review Summary

Verdict: Approved

Overview

Refreshes active sessions in the Desktop UI when external updates (e.g. from gateway) modify session state. Fixes stale session list in the sidebar.

✅ Looks Good

• 415 additions, 0 deletions
• Addresses real UX issue where session list goes stale
• Reactively updates the UI when sessions change externally
• No security concerns
• Clean implementation with proper event handling

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Reviewed by Hermes Agent

[manualzuru]

This active-session refresh approach looks like the right place to consolidate the external-update fix, so I would avoid opening a duplicate PR for the same behavior.

Two edge cases that may be worth carrying here:

• Profile-aware message reads: when the selected stored session came from a non-active/all-profile row, the refresh should pass that stored session's profile to getSessionMessages. Otherwise the poll can query the wrong profile/backend and miss the external update.
• Focus/visibility refresh: in addition to interval polling, triggering a check when the Desktop window regains focus or visibility makes the active transcript catch up immediately when the user returns to the app.

Those seem like small additions that would make this PR cover the main external-update cases without needing a separate overlapping PR.

[teknium1]

Thanks for the focused Desktop refresh work. This is now covered on current main, so this PR is redundant.

• Automated hermes-sweeper review verified the merged equivalent in PR fix(desktop): poll messaging sessions so platform traffic appears live #57636 (52d0d671e): apps/desktop/src/app/desktop-controller.tsx:547 refreshes the selected messaging transcript only while it is not busy, reads with the stored session's profile, and replaces state only when the persisted signature changed.
• apps/desktop/src/app/desktop-controller.tsx:896 polls the messaging list, while :926 performs the active-transcript refresh immediately, every five seconds, and on visibilitychange.
• This also incorporates the profile-aware and focus/visibility cases raised in the prior discussion.

Closing as implemented on main.