ci: simplify and harden release health

[abrichr]

What changed

• Replace the 1,435-line generic release-health framework from ci: detect unreleased work and silently skipped publishes #57 with a 590-line Capture-specific monitor.
• Reduce scheduled checks from eight per day to two, while retaining immediate evaluation after a non-successful release run.
• Keep one paginated, reopenable issue without committed mutable state.
• Treat successful exact-main retries as resolving older failed attempts and preserve unknown PyPI state as unknown.

Why

PR #57 solved a real launch risk but merged with more framework and recurring hosted-CI cost than this single-package repository needs. This follow-up preserves the release-gap signal while removing configuration indirection, cross-repository abstractions, and unnecessary scheduled runs.

Nothing here publishes a package. Publication remains the deliberate protected release.yml workflow.

Validation

• 11 focused offline release-state scenarios
• live read-only GitHub/PyPI evaluation against current Capture state
• Ruff check and format check
• Python compilation on the system interpreter
• actionlint on the workflow
• clean diff check
• wheel and sdist build
• distribution-boundary verification on both archives