v0.6.2: the v0.5 review follow-ups

Fixes from the independent review of v0.5 (#14). None of them let a change through the gate.

Security

• attest --out and --dir stay inside the repository. They could write anywhere, so an agent talked into passing --out ~/.bashrc or --out package.json would overwrite it with JSON. The target must now be a .json file inside the repository, and anything already there must be an attestation. Otherwise attest exits 2 and writes nothing.

Fixed

• --note followed by another flag (--note --against b.ts) recorded the flag as the note. A bare flag after --note is now a missing value. Notes that merely start with -- still work.
• On a pull request, a coverage base that is the pull request's own commit (HEAD~0, the branch's own name) would cover nothing. verify now exits 2 instead. On a push to main, where base and HEAD are the same, it still runs.

Changed

• The report says when a folder's own policy replaced the root one. Running from a subfolder with its own .slipmark/policy.json uses that policy only. The report now says the root's policy wasn't read, checked on the branch the policy came from, so a branch that deletes the root policy can't hide it. docs/attestation.md explains the rule.

The review itself found one problem in these fixes, now fixed. The full list is in CHANGELOG.md.

- uses: founder-ship-it/Slipmark@v0.6.2

npx slipmark@0.6.2 init