Pre-warm cipher decryption on desktop to remove vault search lag

[mikolajbuczak]

🎟️ Tracking

Community contribution. No Jira ticket.

📔 Objective

After signing in to the desktop app, typing in the vault search bar produces no
filtered results for the first few seconds (~3s on a typical vault). The lag
scales with vault size.

The vault component composes its filtered list as
combineLatest([cipherListViews$, filter$, searchText$]) (see
apps/desktop/src/vault/app/vault-v3/vault.component.ts:397-419). The first
subscription to cipherListViews$ is what triggers SDK decryption of the
entire vault, and that only happens when the user navigates to the vault page.
Until decryption completes, combineLatest does not fire, so the search input
appears unresponsive.

This change adds a pre-warm subscription to cipherListViews$ in
AppComponent for the active user. Because cipherListViews$ is wrapped in a
per-user shareReplay (libs/common/src/vault/utils/observable-utilities.ts),
by the time the vault page mounts the cache is hot and basic search is
instantaneous.

switchMap(account => account?.id ? cipherListViews$(account.id) : EMPTY)
handles login/logout/account switches automatically; takeUntil(this.destroy$)
matches the existing teardown pattern in this file.

Verification

Two new specs in libs/common/src/vault/services/:

• search.service.perf.spec.ts benchmarks basic search across
  100/1000/5000/10000 ciphers. Median for 10000 ciphers: 5.97ms — confirms
  SearchService itself is not the bottleneck.
• vault-search-pipeline.lag.spec.ts reproduces the multi-second lag in a
  unit test by simulating a delayed cipherListViews$ first emission, and
  asserts that pre-warming reduces user-visible latency from ~3010ms to <200ms
  (observed 9ms locally).

All 642 specs in libs/common/src/vault/ pass. ESLint and Prettier pass on
the modified files.

📸 Screenshots

N/A — no UI changes.

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[bitwarden-bot]

Thank you for your contribution! We've added this to our internal tracking system for review.
ID: PM-36444
Link: https://bitwarden.atlassian.net/browse/PM-36444

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