chore(scripts): remove one-off scripts nothing runs

Nothing in package.json, the workflows, the Dockerfile, the docs or the
other scripts named these: the bench result dumps of v1.44 and v1.45
that no document cites, the version-pinned release checks, the v1.42
correlation dry run, the read-only diagnostics and their cleanup and
conversion companions for defects fixed long ago, the one-off locale
builder from v1.4.25, and the four June seeders for the demo account.

Kept: the two bench results the benchmarks doc cites, the Google Health
sleep repair (the duplicate-night issue is still open), the demo
migration its password guard reads, the column-reader sweep its test
imports, and the message-bundle tools. The scripts README now lists the
kept tools that it did not name before and drops a reference to a file
that does not exist.

scripts/i18n-key-tool.mjs

@@ -1,5 +1,5 @@
 /**
- * One-shot helper for a text sweep across the six locale bundles.
+ * One-shot helper for a text sweep across every locale bundle.
  *
  *   node scripts/i18n-key-tool.mjs drop  <dotted.key> [...]
  *   node scripts/i18n-key-tool.mjs set   <locale> <dotted.key> <value>