update-to-versionlisted

# update-to-version The recurring half of the versioned-standard mechanism. `align-to-standards` adopts the standard the first time; **this** brings an already-aligned repo up to a newer version - the way you'd bump a dependency, not re-scaffold from scratch. The repo records the version it is aligned to in **`.standards-version`**. Updating reads the **delta** between that version and the target, applies only what changed, and proves the result with `self-verify`. ## Preconditions - The repo has a `.standards-version`. If it does not, this is a first adoption - use `align-to-standards` instead (which writes it). ## Steps 1. **Read current and target versions.** Current = `.standards-version`; target = the requested version (or the standard's latest). Equal? There is nothing to apply - skip to step 6 and self-verify. 2. **Read the delta, not the whole standard.** The delta is the **file diff between the two versions' shipped trees**: in a checkout of the standards repo, `git diff <current-ref> <target-ref> -- standard/`. A ref is a release tag where tags exist; where they do not, it is the commit each version was cut at, and `VERSION`'s own history names those - `git log --format='%h %s' -- VERSION`, then `git show <commit>:VERSION` to see which version a commit carries. Nothing else sees all of the delta. The manifest and the changelog index that diff; neither stands in for it. - The **manifest diff** (`standard.manifest.json`, ADR-005, k