[PM-37255] feat: Add fill-assist targeting rules data layer

[aj-rosado]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-37255

📔 Objective

Adds the data layer for caching and managing fill-assist targeting rules, including CSS selector parsing and the self-managing sync manager.

Changes:

• FillAssistRules — domain model with HostRule and SelectorClause(tag, id, name, type, role); CSS selectors are parsed at sync time, not at autofill time
• FillAssistDiskSource / FillAssistDiskSourceImpl — per-server SharedPreferences storage (keyed by fillAssistRulesUrl); includes CURRENT_CACHE_VERSION migration to invalidate cached data when parsing logic changes
• FillAssistManager / FillAssistManagerImpl — self-managing singletonthat syncs on serverConfigStateFlow changes; uses a 6-hour timestamp throttle before checking the manifest CID; CSS forms parsed from all pathnames, pooled and merged by category (one HostRule per form type per host); shadow DOM selectors (>>>) use the last segment for matching
• FillAssistModule — Hilt DI bindings

[codecov]

Codecov Report

❌ Patch coverage is 76.42857% with 33 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.34%. Comparing base (f57a7d0) to head (61db0cd).

Files with missing lines	Patch %	Lines
...den/data/autofill/manager/FillAssistManagerImpl.kt	72.50%	9 Missing and 24 partials ⚠️

Additional details and impacted files

@@                          Coverage Diff                           @@
##           PM-37255/fill-assist-network-layer    #6991      +/-   ##
======================================================================
- Coverage                               86.47%   86.34%   -0.14%     
======================================================================
  Files                                     873      878       +5     
  Lines                                   63670    63892     +222     
  Branches                                 9234     9272      +38     
======================================================================
+ Hits                                    55059    55166     +107     
- Misses                                   5436     5527      +91     
- Partials                                 3175     3199      +24     

Flag	Coverage Δ
app-data	17.36% <76.42%> (+0.13%)	⬆️
app-ui-auth-tools	18.98% <0.00%> (-0.05%)	⬇️
app-ui-platform	16.45% <0.00%> (-0.04%)	⬇️
app-ui-vault	27.75% <0.00%> (-0.07%)	⬇️
authenticator	6.19% <0.00%> (-0.03%)	⬇️
lib-core-network-bridge	4.09% <0.00%> (-0.02%)	⬇️
lib-data-ui	1.14% <0.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.