Reconcile snapshot exporter merge state

[punk6529]

Problem

PR #262 merged the release evidence issue snapshot exporter and closed issue #261, but the durable autonomous run state on main still records Queue Item 125 as active and PR #262 as open. The roadmap verification metadata also intentionally distinguished PR #262 from the latest merged baseline while the PR was open; now that PR #262 is merged, the repo should record the final merge evidence and move the queue forward.

Scope

• Record PR Add release evidence issue snapshot exporter #262 final head, squash merge commit, CI run, CodeRabbit result, review-thread resolution, and issue Add release evidence issue snapshot exporter #261 closure in ops/AUTONOMOUS_RUN.md.
• Mark Queue Item 125 as merged in PR Add release evidence issue snapshot exporter #262.
• Add Queue Item 126 for this reconciliation slice.
• Refresh ops/ROADMAP.md verification metadata so PR Add release evidence issue snapshot exporter #262 is the latest merged baseline.
• Preserve blocked public-beta and production-release readiness claims.

Non-goals

• Do not change contract behavior.
• Do not add or complete retained evidence for public beta or production release.
• Do not close issues Retain public beta evidence: external_audit_report #215 through Retain production release evidence: post_audit_remediation #231.

Acceptance criteria

• ops/AUTONOMOUS_RUN.md reflects PR Add release evidence issue snapshot exporter #262 merged as squash commit 19263b048fc8dc8e0fe7c834e206e623d8fb944e.
• Queue Item 125 is no longer active.
• ops/ROADMAP.md verification metadata identifies PR Add release evidence issue snapshot exporter #262 as the latest merged baseline.
• Focused readiness, manifest, checksum, changelog, heading, and whitespace checks pass.