feat: blueprint report — KSP processor + Gradle plugin + HTML report

[keymusicman]

Summary

Adds an end-to-end blueprint report pipeline as two new Gradle modules:

• blueprint-report-ksp — KSP annotation processor that scans @Preview composables, collects widthDp/heightDp/name/group parameters, and emits a blueprint-manifest.json per package. Also generates __Blueprint_ wrapper composables used by the renderer.
• blueprint-report-gradle — Gradle plugin exposing two tasks:
  • blueprintCapture — invokes the compose-preview-renderer and Robolectric fallback to screenshot each preview; respects backgroundAlpha, contentAlpha, widthDp, heightDp, and DPI from the DSL/manifest.
  • blueprintReport — consumes captured images and the manifest to produce a self-contained HTML report grouped by package, with a resizable sidebar, package filter, and function-name display for named previews.

How to run

Execute ./gradlew :example:blueprintReport to generate the report for the example module. The report will be in the example/build/reports/blueprint/blueprint-report.html

[keymusicman]

@GusWard I haven’t prepared the KSP module and Gradle plugin for publishing yet. Let me know if you want me to do it, or if you’ll handle it on your side