fix: authored-link normalization JSX range matching

[mvvmm]

What & why

Bumping @cloudflare/nimbus-docs to 0.13.1 in cloudflare-docs fails at astro check with Nimbus authored-link normalization failed ... ambiguous JSX range — 364 of 9309 MDX files crash.

Root cause: staticHrefOffsets re-parses each JSX element's raw text as TSX and matches the TypeScript-computed node range against satteri's mdast position. TypeScript's JsxElement.getEnd() includes trailing trivia (and even the wrapper's );), so the end offset drifts and the lookup misses → "ambiguous JSX range". The same raw text also isn't always valid JSX: code blocks inside JSX elements can contain { (interpreted by TS as a JSX expression) and blockquote markers (> ) span the element's raw slice.

Changes:

• Match JSX elements by start offset instead of full range — getStart() is precise and unique; the drifting getEnd() was the failure.
• Skip elements without href attributes before the TS round-trip — staticHrefOffsets only ever emits insertions for href-like attributes, so parsing is unnecessary (and crash-prone) otherwise.
• Reconcile attributes by name instead of index — when TS can't parse a mangled attribute (e.g. blockquote markers), skip it rather than failing the whole source.

Verified: full scan of cloudflare-docs docs/partials/changelog goes from 364 failures to 0. Three regression tests added.

Checklist

• A maintainer approved this work (lgtm+ on my issue or discussion), or I'm on the team
• Correct tier (framework / starter / registry) per the boundary test
• Edited packages/nimbus-starter-source/, not the templates branch
• Changeset added (create-nimbus-docs changeset if the starter changed)
• pnpm typecheck, pnpm -r test, and pnpm templates:check all green

[pkg-pr-new]

pnpm add https://pkg.pr.new/@cloudflare/create-nimbus-docs@124

pnpm add https://pkg.pr.new/@cloudflare/nimbus-docs@124

commit: c83cfdf

[MohamedH1998]

Should we only normalize href on native elements? If a native html cannot be read, might be worth returning an error instead of skipping it.

[MohamedH1998]

Closing this as it's resolved by #138