Suite6 + P8: Comprehensive task tests + Roborazzi scaffolding

Suite6_ComprehensiveTaskTests ports iOS tests not covered by Suite5/10
(priority/frequency picker variants, custom intervals, completion history,
edge cases).

Roborazzi screenshot-regression scaffolding in place but gated with @Ignore
until pipeline is wired — first `recordRoborazziDebug` run needs manual
golden-image review. See docs/screenshot-tests.md for enablement steps.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

composeApp/build.gradle.kts

@@ -11,6 +11,7 @@ plugins {
     alias(libs.plugins.composeHotReload)
     alias(libs.plugins.kotlinxSerialization)
     alias(libs.plugins.googleServices)
+    alias(libs.plugins.roborazzi)
     id("co.touchlab.skie") version "0.10.7"
 }
 
@@ -133,6 +134,15 @@ kotlin {
                 implementation(libs.androidx.test.core.ktx)
                 implementation(libs.androidx.testExt.junit)
                 implementation("androidx.work:work-testing:2.9.1")
+                // Roborazzi screenshot regression tooling (P8). Runs on the
+                // Robolectric-backed JVM unit-test classpath; no emulator
+                // required. Add compose ui-test so the rule's composeRule
+                // parameter compiles.
+                implementation(libs.roborazzi)
+                implementation(libs.roborazzi.compose)
+                implementation(libs.roborazzi.junit.rule)
+                implementation(libs.compose.ui.test.junit4.android)
+                implementation(libs.compose.ui.test.manifest)
             }
         }
         val androidInstrumentedTest by getting {