build: add public API dumps with binary-compatibility-validator

[nickolas-dimitrakas]

Summary

Adds a committed, reviewable record of the public API surface of android-core and android-kit-base, and a check that fails when a change moves it.

• Applies kotlinx binary-compatibility-validator 0.18.2 to both published modules and commits the generated dumps (android-core/api/android-core.api, android-kit-base/api/android-kit-base.api). BuildConfig is ignored; members annotated @RestrictTo are treated as non-public.
• Runs ./gradlew apiCheck in the existing Unit Tests job, so a signature change fails the build until the dump is regenerated with ./gradlew apiDump and the diff is part of the pull request.
• Adds scripts/check_api_dump.py, which compares the dumps against the base branch and classifies each changed class. A change to any class outside com.mparticle.internal, or to an internal class listed in scripts/api-frozen-internals.txt (classes kits import, classes resolved by name, classes named in proguard.pro), fails the job. Other internal changes are reported for review. The step is skipped when the pull request carries the api-change-approved label, the path for an intentional, reviewed API change; because the workflow does not run on label events, push a commit (or rebase) after labelling to re-run it.
• Documents the commands in AGENTS.md.

No source or artifact changes. The dumps describe the compiled surface as it is on main today.

Why

The dump is the baseline for upcoming internal refactoring: it makes every accidental change to the compiled surface (a class or method becoming final, a static moving, an overload appearing) visible in review before it can ship.

Verification

• ./gradlew apiDump on main produces 3,541 declarations for core and 499 for kit-base; ./gradlew apiCheck passes.
• ./gradlew ktlintCheck passes.
• Classifier self-test: removing a public method from AttributionError in the dump exits 2 (frozen); adding a method to internal.UserStorage exits 0 with a reviewable report; a base without dumps is treated as baseline creation and exits 0.

Follow-up

The api-change-approved label does not exist yet and needs to be created in the repository settings.

🤖 Generated with Claude Code

[github-actions]

📦 SDK Size Impact Report

What the SDK adds to a minified release APK.

Measured against an empty baseline app. Unlike the Rokt kit, android-core ships no Compose and no resources, so there is nothing here that a host app would already provide.

mParticle Core SDK

Metric	Target branch	This PR	Change
APK size	119.79 KB	119.79 KB	+2 bytes
Download size	117.60 KB	117.60 KB	+2 bytes
Dex bytes	213.75 KB	213.75 KB	0 bytes

➡️ SDK size impact change is minimal.

Raw measurements

Target branch:

{"baseline_dex_bytes": 0, "baseline_download_bytes": 2509, "baseline_install_bytes": 7523, "core_dex_bytes": 218884, "core_download_bytes": 122934, "core_install_bytes": 130185}

This PR:

{"baseline_dex_bytes": 0, "baseline_download_bytes": 2514, "baseline_install_bytes": 7530, "core_dex_bytes": 218884, "core_download_bytes": 122941, "core_install_bytes": 130194}

_{Measured 1d39db4 merged into eb2b44b}

[github-actions]

📦 SDK Size Impact Report

What the SDK adds to a minified release APK.

Measured against a Compose + Material3 reference app, so these are the costs on top of an app that already ships Compose. The reference app's dependencies are a documented convention, not a measured average: see size-report-rokt/README.md.

mParticle Core + Rokt kit

Metric	Target branch	This PR	Change
APK size	1.26 MB	1.26 MB	0 bytes
Download size	1.24 MB	1.24 MB	+2 bytes
Dex bytes	2.22 MB	2.22 MB	0 bytes

Rokt SDK+ umbrella (adds the payment extension)

Metric	Target branch	This PR	Change	On top of mParticle Core + Rokt kit
APK size	6.53 MB	6.53 MB	0 bytes	+5.27 MB
Download size	6.43 MB	6.43 MB	-3 bytes	+5.19 MB
Dex bytes	7.10 MB	7.10 MB	0 bytes	+4.89 MB

➡️ SDK size impact change is minimal.

Raw measurements

Target branch:

{"baseline_dex_bytes": 1829108, "baseline_download_bytes": 1240062, "baseline_install_bytes": 1300934, "kit_dex_bytes": 4156052, "kit_download_bytes": 2540334, "kit_install_bytes": 2623275, "sdkplus_dex_bytes": 9278708, "sdkplus_download_bytes": 7978468, "sdkplus_install_bytes": 8148975}

This PR:

{"baseline_dex_bytes": 1829108, "baseline_download_bytes": 1240062, "baseline_install_bytes": 1300934, "kit_dex_bytes": 4156052, "kit_download_bytes": 2540336, "kit_install_bytes": 2623275, "sdkplus_dex_bytes": 9278708, "sdkplus_download_bytes": 7978465, "sdkplus_install_bytes": 8148975}

_{Measured 1d39db4 merged into eb2b44b}

[cursor]

PR Summary

Low Risk
Build and CI configuration change only, introducing automated binary API surface tracking without affecting production runtime code.

Overview
Integrates the kotlinx.binary-compatibility-validator Gradle plugin into android-core and android-kit-base to automatically track and enforce public API consistency.

Adds baseline API signature dumps and integrates validation into the CI pull request workflow via ./gradlew apiCheck and a custom classifier script scripts/check_api_dump.py. The CI check prevents unauthorized modifications to public and frozen internal interfaces unless the PR is tagged with the api-change-approved label. Documentation for checking and regenerating dumps is also added to AGENTS.md.

^{Reviewed by Cursor Bugbot for commit 1d39db4. Bugbot is set up for automated code reviews on this repo. Configure here.}