[PM-9420] - add cipher$ observable to cipher service

[jaasen-livefront]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-9420

📔 Objective

This PR adds a shared cipherView$ method to CipherService for retrieving a single decrypted CipherView from local vault state by cipher ID.

It replaces several direct get + decrypt call sites with cipherView$, ensuring consumers use the already-decrypted local cipher views and receive updates consistently when vault state changes.

Changes include:

• Added cipherView$(userId, cipherId) to the cipher service abstraction and implementation.
• Updated browser and web vault flows to use cipherView$.
• Updated vault item dialog refresh/cancel behavior to reload from local decrypted state.
• Added unit coverage for matching, missing, and nullish cipher view state.

📸 Screenshots

N/A

[github-actions]

🤖 Bitwarden Claude Code Review

Overall Assessment: APPROVE

Reviewed the new cipherView$(userId, cipherId) method added to CipherService (abstraction + implementation) and the call sites migrated from the get + decrypt pattern across browser, web, and the shared vault-item dialog. The refactor is consistent, the new method has unit coverage for matching, missing, and nullish (cipherViews$ === null) cases, and the behavioral differences at each call site are equivalent to or an improvement over the prior code.

Code Review Details

No findings at or above the reporting threshold.

Notes from the analysis (no action required):

• The new cipherView$ can emit undefined for a missing cipher. Several call sites (open-attachments, web vault getPasswordFromCipherViewLike, vault-item-dialog.processChanges) dereference the result without a null guard, but each already dereferenced an effectively-equivalent unguarded result in the prior get + decrypt code, so this is not a newly introduced regression.
• assign-collections.component.ts adds filter((cipher): cipher is CipherView => cipher != null), which correctly waits for a valid decrypted cipher before the downstream combineLatest fires.
• All consumers wrap cipherView$ in firstValueFrom, taking only the first emission, which is the correct usage for these one-shot reads.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud