Add generated TUS protocol contract canary

[kvz]

Why: this is the Android companion canary for the contract-generated TUS effort. tus-android-client delegates wire-level behavior to tus-java-client, so this PR keeps protocol truth generated from the shared contract while proving Android-specific content URI, storage, callback, and request-observation paths still work.

Experimental Status

Experimental work: this PR is part of an exploratory contract/generated docs and SDK effort, and is intentionally kept as a Draft while the approach is validated.

What Changed

• add a generated test-side TUS protocol/feature fixture from API2 contracts
• add a Robolectric test that consumes the generated singleUploadLifecycle feature and verifies TusPreferencesURLStore satisfies the generated store-resume-url primitive
• add checked-in Robolectric proofs for upload callbacks, upload body headers, custom request headers, request-ID headers, terminate upload, creation-with-upload, deferred-length upload, request lifecycle hooks, and retry-offset recovery
• have those proofs read contract-owned scenario facts from scenario JSON instead of repeating protocol/API facts locally
• extend the shared Android devdock scenario helper with contract-document readers for custom headers, request-ID toggles, request-ID header names, terminate-upload facts, request lifecycle expectations, and retry-offset recovery expectations
• allow sibling and CI-nested tus-java-client Gradle composite builds so Android QA can use the companion Java branch before the new hooks/deferred-length APIs are released to Maven
• tidy the CI trigger block by removing a misplaced runs-on, adding ready_for_review, and enabling manual workflow_dispatch

Validation

• ANDROID_HOME=/Users/kvz/.cache/devdock/android-sdk ANDROID_SDK_ROOT=/Users/kvz/.cache/devdock/android-sdk ./gradlew check
• api2/bin/cli.ts contracts sdks --no-motd --target tus --platform android --sdk-root ../tus-android-client --compare-existing
• api2/bin/cli.ts contracts sdks qa --no-motd --target tus --platform android --dry-run
• core/bin/devdock.ts exec tstrun cmds/ContractsCommand.vitest.ts -vv --max-time-per-test 420 from the API2 companion checkout
• core/bin/devdock.ts exec tstrun system/sdk_examples/android-tus-transloadit-assembly-upload.test.ts -vv --max-time-per-test 900 from the API2 companion checkout
• GitHub Actions on this PR: android (17) and android (21) passed on commit 21b3cdf

Companion PRs (tus org only)

• tus-js-client: Mark protocol versions as generated tus-js-client#872
• tus-go-client: Add generated TUS protocol canary tus-go-client#6
• tus-py-client: Add generated TUS protocol canary tus-py-client#114
• tus-java-client: Add generated TUS protocol contract canary tus-java-client#149

Notes

Standalone CI checks out tus-java-client@tus-gen into the Android checkout and settings.gradle accepts both sibling and nested composite builds. That keeps this Draft consumable before the Java lifecycle hooks and deferred-length API are released to Maven.

Latest: Android now proves deferred-length uploads, request lifecycle hooks, and retry-offset recovery. The latest retry proof simulates one post-PATCH IO failure from scenario data, observes the recovery HEAD, and finishes with the final PATCH against real API2/tusd.