Bump minSdkVersion to 23

[Copilot]

This PR...

Raises minimum Android API level from 21 (Lollipop) to 23 (Marshmallow).

Considerations and implementation

Updated minSdk configuration in both modules:

• flow/build.gradle.kts: Library module now requires API 23+
• app/build.gradle.kts: Sample app now requires API 23+

How to test

1. Build succeeds: ./gradlew clean build
2. Verify APK manifest declares minSdkVersion="23"

Test(s) added

None required - configuration-only change. Existing unit tests validate functionality on API 23+.

Screenshots

N/A - build configuration change only.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Bump minSdkVersion to 23</issue_title>
<issue_description></issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Bump minSdkVersion to 23 #491

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[Copilot]

Pull request overview

This PR raises the minimum Android SDK version from API 21 (Lollipop) to API 23 (Marshmallow) across all project modules.

Key Changes:

• Updated minSdk configuration in both the library module (flow) and sample app module (app)

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
flow/build.gradle.kts	Updated library module minSdk from 21 to 23
app/build.gradle.kts	Updated sample app module minSdk from 21 to 23

Review Summary:

The changes are clean and consistent. Both modules have been updated to require API 23 as the minimum SDK version. I verified that:

• ✅ Both modules are updated consistently (library and sample app)
• ✅ No API version checks in the codebase that would need updating
• ✅ No manifest files directly referencing minSdkVersion
• ✅ Configuration-only change as stated in the PR description

Note: The documentation files .github/copilot-instructions.md and custom-instructions/repo/.github/copilot-instructions.md still reference "minimum API 21" and should be updated in a follow-up to reflect this change, but those files are outside the scope of this PR.