Decouple generators from Anvil and move them to KSP (duckduckgo#8397)

Task/Issue URL:
https://app.asana.com/1/137249556945/project/1214119362406643/task/1214427159097979?focus=true

### Description
Move the code generators from Anvil compiler to KSP.

### Steps to test this PR
All tests pass, we have:
* existing integration tests
* new tests added in this PR


Also smoke test the app

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **High Risk**
> Replaces the custom `:anvil-compiler` annotation processor with a new
KSP-based processor and updates multiple modules’ build configuration;
codegen/DI wiring changes can break compilation or runtime bindings
across the app.
> 
> **Overview**
> Migrates DuckDuckGo’s custom Anvil-based code generation off the
`:anvil-compiler` module and onto a new KSP module, `:anvil-ksp`.
> 
> Updates affected Android modules to apply the KSP plugin and swap
`anvil project(':anvil-compiler')` for `ksp project(':anvil-ksp')`.
> 
> Removes the Anvil `CodeGenerator` implementations (e.g., plugin
points, remote feature toggles, workers, view models, activity starters)
and introduces a KSP implementation for `@ContributeToActivityStarter`
(`ContributeToActivityStarterProcessor` + provider) that generates the
same activity/params mapper bindings and optional deeplink parsing
helpers.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
34598ec. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: aitorvs

ad-click/ad-click-impl/build.gradle

@@ -38,7 +38,7 @@ android {
 }
 
 dependencies {
-    anvil project(path: ':anvil-compiler')
+    ksp project(':anvil-ksp')
     implementation project(path: ':anvil-annotations')
     implementation project(path: ':browser-api')
     implementation project(path: ':ad-click-api')

android-design-system/design-system-internal/build.gradle

@@ -48,7 +48,6 @@ dependencies {
     implementation project(path: ':design-system')
 
     implementation project(path: ':di')
-    anvil project(path: ':anvil-compiler')
     implementation project(path: ':anvil-annotations')
     implementation project(path: ':app-build-config-api')
     implementation project(':internal-features-api')

android-design-system/design-system/build.gradle

@@ -18,6 +18,7 @@ plugins {
     id 'com.android.library'
     id 'kotlin-android'
     id 'com.squareup.anvil'
+    id 'com.google.devtools.ksp'
 }
 
 apply from: "$rootProject.projectDir/gradle/android-library.gradle"
@@ -45,6 +46,7 @@ android {
 }
 
 dependencies {
+    ksp project(':anvil-ksp')
 
     if (rootProject.ext.proprietaryFontAvailable) {
         implementation "com.duckduckgo:ddg-proprietary-fonts:1.0.2"
@@ -55,7 +57,6 @@ dependencies {
     implementation project(path: ':common-utils')
 
     implementation project(path: ':di')
-    anvil project(path: ':anvil-compiler')
     implementation project(path: ':anvil-annotations')
     implementation project(path: ':app-build-config-api')
     implementation project(':internal-features-api')

anrs/anrs-impl/build.gradle

@@ -18,12 +18,13 @@ plugins {
     id 'com.android.library'
     id 'kotlin-android'
     id 'com.squareup.anvil'
+    id 'com.google.devtools.ksp'
 }
 
 apply from: "$rootProject.projectDir/gradle/android-library.gradle"
 
 dependencies {
-    anvil project(':anvil-compiler')
+    ksp project(':anvil-ksp')
     implementation project(':anvil-annotations')
 
     implementation project(':app-build-config-api')

anrs/anrs-internal/build.gradle

@@ -28,7 +28,7 @@ dependencies {
 	implementation project(":anrs-impl")
 	implementation project(":anrs-store")
 
-    anvil project(':anvil-compiler')
+    ksp project(':anvil-ksp')
     implementation project(':anvil-annotations')
     implementation project(':di')
     implementation project(':design-system')