- change required acknowledgement phrase to "I ACCEPT RISK"
- apply typed phrase requirement to Gemini and Antigravity add-account flows
- keep CLI/server and UI phrase validation aligned
- update antigravity responsibility unit test
- replace issue #622/#619 references with issue #509 across CLI and dashboard
- shorten acknowledgement phrase to "I ACCEPT AGY RISK" for faster typing
- rename acknowledgement payload field to reviewedIssue509 and update tests