fix(desktop): persist zoom level across conversations

[SongotenU]

Problem

When a user zooms in (Cmd+=) in one conversation and switches to another via the sidebar, the zoom level resets to default. This happens because Chromium stores per-URL zoom levels in per_host_zoom_levels, and each conversation has a unique hash route (...#/session_a vs ...#/session_b). The unseen URL gets a fresh 1.0 zoom.

Root Cause

The app already has zoom persistence infrastructure:

• installZoomShortcuts() — intercepts Cmd+=/Cmd+-/Cmd+0 and writes the zoom level into both webContents.setZoomLevel() and localStorage
• setAndPersistZoomLevel() / restorePersistedZoomLevel() — round-trip through localStorage so zoom survives restarts

But restorePersistedZoomLevel was called only from a once(did-finish-load) on mainWindow. It was not wired into:

• Session windows (detached chats)
• Hash-route navigations inside the SPA (same window, new URL = new per-host entry)

Fix

Move restorePersistedZoomLevel from the one-shot mainWindow callback into wireCommonWindowHandlers, which is already shared by every window (main + session). Now every did-finish-load — cold start, session window open, reload, and hash-route transitions — re-applies the user persisted zoom level.

Changes

• apps/desktop/electron/main.cjs: +8 −1
• Move restorePersistedZoomLevel(win) into wireCommonWindowHandlers as a did-finish-load listener
• Remove the now-redundant call from mainWindow one-shot callback

Testing

• Zoom in → switch conversation → zoom persists
• Zoom in → close & reopen window → zoom persists
• Zoom in → open session window → zoom is restored
• Cmd+0 resets zoom → persists across navigation

[tonydwb]

Code Review Summary

Verdict: Approved

Simple, focused fix: persists zoom level across desktop conversations. Single file, minimal change.

Looks Good

• Clean, well-scoped
• No security concerns

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Reviewed by Hermes Agent

[teknium1]

Thanks for the focused zoom-persistence investigation. The issue remains relevant, but this patch needs a small rework before it can cover its stated route-switch path.

Problems

• Desktop uses HashRouter at apps/desktop/src/main.tsx:42. Electron documents that an in-page navigation does not reload and emits did-navigate-in-page; therefore the PR's did-finish-load listener does not run for the hash-route conversation switch it describes.
• The patch targets apps/desktop/electron/main.cjs, but current main moved this wiring to apps/desktop/electron/main.ts:6972-6981; it will not apply cleanly.
• There is no route-navigation regression test. Current zoom tests cover show/restore only (apps/desktop/electron/zoom.test.ts:67-102).

Suggested changes

• Port the shared wiring to main.ts, add the in-page navigation reassertion, and cover that event with a focused regression test.
• Please reconcile the scope with linked fix(desktop): app-level zoom that sticks, and session windows that inherit parent size #51582 before salvage, since it addresses the same route-level behavior with a broader architecture.

Automated hermes-sweeper review.

[teknium1]

Merged via PR #66989 (#66989) — your fix is on main with your authorship preserved. Thanks for the clean root-cause analysis on the per-host zoom levels and the once-spent listener!

Your branch targeted the pre-TypeScript main.cjs (since migrated), so the change was surgically reapplied onto current main under your authorship rather than cherry-picked. Half of your original fix — moving zoom restore into wireCommonWindowHandlers so session windows are covered — had already been independently adopted on main; the merged PR ships the remaining half (once('did-finish-load') → on(...)) so zoom now survives crash-recovery reloads and in-place navigations too.

Closing this PR in favor of the merged salvage. Thanks again!