docs: record final showcase automation evidence

[KXHXK]

What changed

• Record PR release: define showcase and owner acceptance gates #23, main merge 7bb9ecd, and main run 30629194460 as the current authoritative automation evidence.
• Update the handoff, current state, release audit, daily log, CI evidence, and document index.
• Record that the clean main Compose job built the uv 0.11.28 image and passed three-business effects plus API/MCP restart recovery.
• Keep Showcase awaiting owner validation and Product Release closed.

Validation

• Release/document contract tests: 16 passed.
• Repository safety: passed.
• Document index: 122 current Markdown files, passed.
• git diff --check: passed.

This PR changes evidence and its drift contract only; it does not change the Agent runtime or public deployment boundary.