Pr Prep

Run AGENTS.md, "Before opening a pull request" (every item) and the pull request prose rule under "Patches and commits": title and body say what and why, nothing the commits already say, no "Test plan" section, no em dashes. On top of it:

• When a doc block, @type, @treturn or config.ld changed, run make doc-site LUA=lua5.4, the CI target, and read its exit status: LDoc quits on a module it cannot place with a line that says neither "warning" nor "error", so a grep for those passes a failed run. Then check the links land on types, not functions.
• Compare git diff against git diff -w for stray whitespace; bash tools/checks/pre-commit covers the trailing blank line on staged files.
• Fixup commits stay unsquashed unless squashing was explicitly requested; the maintainer reviews them before they are folded.
• Every function the diff touches is re-read whole before the hand-back: is a new branch this function's job or its caller's; is a condition with stack juggling a predicate helper; did the new shape leave a guard redundant.
• The hand-back lists the findings of your own review the change does not apply, each with its reason; none is dropped in silence.
• The hand-back carries the test matrix: for each guard or mechanism the change adds, operations by types by outcomes, each cell with its test or the reason it is not covered.
• Every example that uses a binding the change touches is run through its own setup.sh and cleanup.sh, and the hand-back says of each whether it ran, only loaded, or was not run, and why.
• The body opens with the failure or the need in one plain sentence, then what the change does, then what it depends on: three short paragraphs at most; bash tools/checks/pr-body.sh <file> before posting it.
• After any force-push, re-read the title and body against the branch as it now stands.