Use gradle plugin for Room to prevent it stopping caching

[CDRussell]

Task/Issue URL: https://app.asana.com/1/137249556945/task/1213076149941930

Description

Fixes Room schema export by switching to the Room Gradle plugin. Several modules were using annotationProcessorOptions to configure the schema location, but this only works with kapt, not KSP. Since Room is compiled with KSP in these modules, schemas weren't being exported.

Additionally (the original reason I was looking at this), absolute paths were being used which breaks Gradle caching.

Changes

• Added androidx.room Gradle plugin to affected modules
• Replaced annotationProcessorOptions and ksp { arg(...) } with the new room { schemaDirectory(...) }

Why the JSON schema changes/creation
Because many of the DB schema files were missing, and one was wrong. They've been missing for some time.

6 databases were affected:

Database	Missing Schemas
AppDatabase	versions 50-60
VpnDatabase	versions 33-34
RemoteMessagingDatabase	version 2
SitePermissionsDatabase	versions 2-5
VoiceSearchDatabase	version 2
BrokenSiteDatabase	incorrect v1 schema

2 databases were already working (PirDatabase, Autofill databases) because they used the correct ksp { arg(...) } syntax already.

Why this matters

• Enables Gradle build caching (absolute paths in old config broke cache keys)
• Schema JSON files are now correctly exported for migration testing
• Uses the officially recommended Room configuration method

Steps to test this PR

• Fresh install develop, do some stuff in the app then install this branch. Verify no problems in the upgrade

---

Note

Medium Risk
Build config changes span many modules and regenerate schema artifacts; risk is mainly in build/cache behavior and Room migration test expectations rather than runtime logic.

Overview
Migrates Room schema export configuration to the official androidx.room Gradle plugin across multiple modules (including app, vpn-store, broken-site-store, remote-messaging-store, site-permissions-store, voice-search-store, experiments-impl, pir-impl, and autofill-impl). This removes the old annotationProcessorOptions/ksp { arg("room.schemaLocation", ...) } approach, switches schema paths to project-relative ($projectDir/schemas), and adds room { schemaDirectory(...) } plus schema assets wiring for tests.

Adds/updates Room exported schema JSONs for several databases (new versions for AppDatabase, VpnDatabase, RemoteMessagingDatabase, SitePermissionsDatabase, VoiceSearchDatabase) and corrects BrokenSiteDatabase v1 schema (primary key/identity hash), enabling migration testing and improving Gradle build cache reliability.

^{Written by Cursor Bugbot for commit 6b0827e. Configure here.}

[CDRussell]

• Use gradle plugin for Room to prevent it stopping caching #7712 👈 (View in Graphite)
• develop

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[landomen]

I re-ran exp3 and confirmed the issue is fixed. Also tested update from develop to this branch and it works fine 💪