ci: free e2e-gated auto-merge (remove the AI agent)

[mrjasonroy]

What & why

The daily nextjs-version-check loop opened bump PRs that never merged — allow_auto_merge was off and main required an approving review no bot can give, and the failure was swallowed. Zero nextjs-* PRs had ever merged.

The e2e suite is already the reviewer (test-summary is green only if memory + redis + valkey + elasticache pass), so this drives the merge off the checks instead of an AI:

• nextjs-version-check now opens the PR + enables --squash --auto via RELEASE_PAT (a real identity → the PR triggers CI and the merge fires tag-on-version-merge). Degrades gracefully to "PR opens, you merge" if the PAT is unset.
• Removed the ambient-version-agent workflow + doc — it cost ~tens of $/mo on the Anthropic API for an OSS side project and added nothing the e2e gate didn't.
• Added docs/auto-release.md (RELEASE_PAT setup + branch-protection revert).

Repo config already applied: allow_auto_merge + delete_branch_on_merge on; main's required approval dropped, status checks kept.

Setup still needed

Add a fine-grained RELEASE_PAT secret (this repo only; Contents + Pull requests: write). See docs/auto-release.md.

🤖 Generated with Claude Code

[gemini-code-assist]

Code Review

This pull request replaces the AI-based "Ambient Version Agent" documentation with a new "Autonomous releases" workflow documentation (docs/auto-release.md) that relies on GitHub's native auto-merge and a personal access token (RELEASE_PAT). A review comment correctly points out that the example gh api command for restoring branch protection is missing required fields (dismiss_stale_reviews and require_code_owner_reviews), which would cause the GitHub API to fail with a 422 error, and provides a code suggestion to resolve this.

Important

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For more details on the timeline and next steps, please review the Help Documentation.

[gemini-code-assist]

The GitHub REST API for updating branch protection (PUT /repos/{owner}/{repo}/branches/{branch}/protection) is strict about the required_pull_request_reviews object. If you omit dismiss_stale_reviews and require_code_owner_reviews, the API call will fail with a 422 Unprocessable Entity validation error. Adding these fields with default boolean values ensures the command runs successfully.

Suggested change

	gh api -X PUT repos/{owner}/{repo}/branches/main/protection --input - <<'JSON'
	{ "required_status_checks": { "strict": false,
	"contexts": ["lint-and-typecheck", "unit-tests", "test-summary"] },
	"enforce_admins": false,
	"required_pull_request_reviews": { "required_approving_review_count": 1 },
	"restrictions": null, "required_conversation_resolution": true }
	JSON
	gh api -X PUT repos/{owner}/{repo}/branches/main/protection --input - <<'JSON'
	{ "required_status_checks": { "strict": false,
	"contexts": ["lint-and-typecheck", "unit-tests", "test-summary"] },
	"enforce_admins": false,
	"required_pull_request_reviews": {
	"dismiss_stale_reviews": false,
	"require_code_owner_reviews": false,
	"required_approving_review_count": 1
	},
	"restrictions": null, "required_conversation_resolution": true }
	JSON