docs(scripts): drop the stale sync-template-versions.mjs cross-reference (#9977)

The @objectstack/spec entry's `serve.ts` rationale cited
`sync-template-versions.mjs` as an example of a path "named in a comment
rather than read". That stopped being true: packages/create-objectstack's
src/template-version-stamps.test.ts really reads the script
(`fs.readFileSync(SYNC_SCRIPT)` on a `path.join(repoRoot, 'scripts',
'sync-template-versions.mjs')`), and since the collector reconstructs
split-segment join paths that read is what holds the radius — the
create-objectstack entry in this same file already says so.

Comment prose only: no verdict, exit code or declared population changes.
The other two examples in the clause were re-checked against the tree and
both still hold — no test reads `scripts/check-nul-bytes.mjs`, and
`content/docs/protocol/kernel/realtime-protocol.mdx` is named in two
comments in authz-conformance.test.ts and read by nothing.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XqDQYVU5smx29ts9pAErja

Author: claude

scripts/check-cross-package-test-inputs.mjs

@@ -139,11 +139,11 @@ const CROSS_PACKAGE_TEST_INPUTS = {
       // scripts/dist-freshness.test.ts stages a fixture around the root scripts dir
       'scripts/**',
       // `serve.ts` is named in a comment rather than read, the same shape as
-      // `check-nul-bytes.mjs` / `sync-template-versions.mjs` / the realtime
-      // protocol page below, and settled the same way: the literal collector
-      // takes quoted paths without parsing, so a mention forces a declaration,
-      // and declaring the file is cheaper than rewording prose to dodge the
-      // scanner. scripts/publish-smoke-port-collision.test.ts cites it for the
+      // `check-nul-bytes.mjs` / the realtime protocol page below, and settled
+      // the same way: the literal collector takes quoted paths without parsing,
+      // so a mention forces a declaration, and declaring the file is cheaper
+      // than rewording prose to dodge the scanner.
+      // scripts/publish-smoke-port-collision.test.ts cites it for the
       // measurement that justifies its whole existence — `serve.ts` auto-shifts
       // off a busy port whenever `flags.dev` is set, which is the only reason
       // publish-smoke.sh cannot trust the port it asked for. One file, not the