Add CI workflows for building and running the example app

[devin-ai-integration]

Summary

Adds two GitHub Actions CI workflows to hello-android-java, mirroring the equivalent workflows recently merged into hello-android (Kotlin):

• build.yml — Checks out the repo, sets up Java 11 (Temurin), and runs ./gradlew assembleDebug.
• run.yml — Fetches the LaunchDarkly mobile key and flag key from AWS SSM via release-secrets, injects them into the Java source files with sed, builds the APK, launches it on an Android emulator (API 29, x86_64), and validates that the UI displays a successful flag evaluation via uiautomator dump.

All actions are pinned to specific SHAs with version comments and reference links.

Key differences from the Kotlin (hello-android) workflows:

• Java 11 instead of Java 17 — this project uses Gradle 6.7 / AGP 4.1.3, which only support up to Java 15.
• Targeted sed for flag key — only the first occurrence of my-boolean-flag is replaced (the constant declaration on line 21). The second occurrence on line 29 is an == guard that shows an AlertDialog; replacing it too would cause the guard to pass (Java string interning makes == true for identical literals), displaying a dialog that blocks the uiautomator validation.
• 30-second sleep instead of 15 — the older SDK (4.2.2 vs 5.11.0) and emulator startup may need more time for initialization.
• UI dump saved to file before grepping, so the full XML is visible in CI logs on failure.

Action versions used

Action	Version	SHA	Reference
actions/checkout	v4.2.2	11bd71901bbe5b1630ceea73d27597364c9af683	release
actions/setup-java	v4.7.1	c5195efecf7bdfc987ee8bae7a71cb8b11521c00	release
launchdarkly/gh-actions/actions/release-secrets	release-secrets-v1.2.0	bbbbbda684f500766264e7fe327668094ba83d1c	release
jlumbroso/free-disk-space	v1.3.1	54081f138730dfa15788a46383842cd2f914a1be	release
reactivecircus/android-emulator-runner	v2.34.0	324029e2f414c084d8b15ba075288885e74aef9c	release

Review & Testing Checklist for Human

• Targeted sed for flag key is fragile: The sed '0,/my-boolean-flag/{s/...}' only replaces the first occurrence to avoid triggering the == guard on line 29 of MainActivity.java. This works because the constant declaration (line 21) comes before the comparison (line 29). If the source file is reordered, the wrong occurrence could be replaced. Consider whether the app code should use .equals() instead of == for these checks (separate issue).
• Grep pattern assumes flag value: The validation grep -oi 'Feature flag.*is true' assumes the flag evaluates to true. If the flag configuration in LaunchDarkly changes to return false, this will cause CI to fail even though the app is working correctly. Monitor the flag configuration or adjust the validation to accept both values.
• Verify AWS_ROLE_ARN repository variable: The run workflow requires vars.AWS_ROLE_ARN to be set in the repo settings for OIDC-based AWS authentication. This worked in CI, but confirm it's properly documented in repo settings.
• Test plan: Wait for the next PR to verify both workflows run end-to-end. On this PR, both build and run workflows passed CI, which is a good initial sign, but you should validate at least once after merge that ongoing CI remains stable.

Notes

• Both workflows passed CI on this PR after fixing Java version compatibility (11 vs 17) and sed targeting issues.
• SDK key retrieval follows the standard release-secrets pattern used across LaunchDarkly hello-app repos.
• The project uses LaunchDarkly Android SDK 4.2.2 (older than the Kotlin version's 5.11.0). Future updates may require re-testing these workflows.

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Link to Devin Session: https://app.devin.ai/sessions/0b2bb3fc4f5845238a581c78eefd5369
Requested by: rlamb@launchdarkly.com

[devin-ai-integration]

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