ci: add pubky paykit e2e shard

[piotr-iohk]

Description

This PR wires the new Pubky/Paykit E2E coverage into Android CI.

1. Adds a dedicated pubky_paykit shard to the staging E2E matrix, running --mochaOpts.grep "@pubky" against the regtest/network build.
2. Aligns Android contact activity row test IDs with iOS by allowing the shared activity list to use a screen-specific prefix and setting contact activity rows to ContactActivity-*.

The E2E tests themselves were added in synonymdev/bitkit-e2e-tests#147. Keeping this as a separate staging shard isolates Pubky/Homegate/Paykit staging dependency failures from the local-regtest wallet shards.

Preview

N/A

QA Notes

Manual Tests

N/A

Automated Checks

• CI coverage added: Android staging E2E now runs @pubky, which covers Pubky profile/contact flows and public Paykit on-chain contact payment from Feat/pubky profile e2e tests bitkit-e2e-tests#147 (after merge).
• Test ID parity: contact activity rows now use ContactActivity-* on Android, matching iOS for cross-platform E2E assertions.
• Local check: ./gradlew :app:compileDevDebugKotlin passed for the contact activity test-id change.

[claude]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.

[ovitrif]

LGTM