Add badge profile asset tests

[cybercraftsolutionsllc]

Summary

• Adds badge profile coverage for /person/uuid/{uuid} so profile lookups return badge asset IDs for the owner, another signed-in viewer, and an anonymous viewer.
• Adds /person/assets/{uuid} coverage for badge asset metadata, including the image/icon URL the badges tab needs to render.
• Gives people_test.go its own DB setup helper so these tests can be validated without importing unrelated handler tests.

Fixes #876

Validation

• git diff --check
• go test handlers\\people.go handlers\\github.go handlers\\people_test.go -run "^$"

Blocked locally:

• go test ./handlers -run "TestGetPersonByUuidIncludesBadgeIdsForProfileContexts|TestGetPersonAssetsByUuidReturnsBadgeAssetImages" is blocked by the repo's existing generated mocks.Database drift (GetBountyByUnlockCode missing).
• Running the new tests directly needs the repo Postgres test DB at localhost:5532; Docker is installed locally but the daemon is not running, so I could not start docker/testdb-docker-compose.yml here.