remit v0.4.16

Every delivery has a showcase

A draft PR used to arrive with a four-part note and test logs: evidence for an
evaluator more than for the practitioner. Now every delivery carries a showcase
with:

• the problem and the chosen approach;
• optionally, how its evidence was taken: the setup, any stand-in for a real
  service or setting, and a command kept in the repository that takes it again;
• one scenario per line of the brief's ## Judged delivered when section, with
  evidence from runs the builder executed and kept;
• what could not be shown, and why.

Screens are shown by screenshots, APIs by real requests and responses, and
scripts by transcripts.

The builder writes showcase.md beside its kept runs, and the draft PR's
## Showcase section repeats it when it fits, or points to its record. At the gate into accepted, remit fails a
delivery before raising any evaluator when the showcase is missing, has a
scenario citing no kept run, or shows an image no cited run names. The
must-fix goes to a fresh builder and the PR stays draft. A repair that changes
only the showcase or its runs keeps the same candidate: remit records the
repaired showcase, shows it in one PR comment, checks it again and raises the
evaluator on it. An empty build answering any other must-fix is still refused.

The evaluator is handed the showcase and told to open every image it shows,
then say scenario by scenario what it saw. An evaluator that cannot open images
returns BLOCKED, never PASS. A new shipped rubric, showcase, has it judge
whether the evidence shows what each scenario claims.

When the delivery passes into accepted, remit records the showcase with the
images and runs it cites in the item's showcase/ folder. Once that record is
pushed, an open PR gets one comment that shows the showcase with its images,
linked to the record commit when the record is on GitHub. A repair round's superseded screenshots never reach the record's
history.

The installer reports a new outcome, collides: a shipped rubric whose id the
host already uses, in the same gate and section, for text remit has no record of
shipping. The host's rubric stays, the shipped one is
not installed, and the line quotes the shipped text.

Validation: a new unit suite drives real local Git and the synthetic seam and
GitHub fixtures through a screenshot delivery, a missing showcase, an image no
run took (repaired once with a new candidate and once in the runs alone), an
empty build answering a product must-fix, and a transcript-only delivery
through closure. It
asserts that only the accepted evaluator is handed the showcase, and that a
failed round's screenshot never reaches the record. The full Linux unit tier
passes. No live model, harness or real GitHub rendering has been exercised yet.

Upgrade before the next build. An item already published without a showcase
fails the showcase check at its next gate into accepted and is repaired within
the usual build rounds. Items already accepted,
closing revalidation, the four-part note and publication.md are unchanged.