chore: script/bootstrap fails unless node finds every dependency and devDependency in package.json (closes #263)

yarn install exits 0 without touching node_modules whenever
node_modules/.yarn-integrity matches yarn.lock, so a package deleted from
node_modules stayed deleted while bootstrap printed "bootstrap complete".
After the install, bootstrap now asks node for the package.json of every
package listed in dependencies and devDependencies of package.json, and on
the first it cannot find it names the package and the fix:
rm -rf node_modules && make bootstrap. A package whose exports hides its
package.json (ethers, libsodium-wrappers-sumo) makes node throw
ERR_PACKAGE_PATH_NOT_EXPORTED, which it does only after finding the
package, so that error counts as found.

Model: opus-5-5

TODO.md

@@ -45,6 +45,15 @@ but the review is broader than any of them.
 
 # Completed Steps
 
+- 2026-10-06: `script/bootstrap` no longer reports success while node cannot
+  find a package listed in `dependencies` or `devDependencies` of `package.json`
+  ([#263](https://git.eeqj.de/sneak/AutistMask/issues/263)). After the install
+  it asks node for each one's `package.json`, and fails naming the missing
+  package and the fix. yarn skips the install whenever
+  `node_modules/.yarn-integrity` matches `yarn.lock`, so a package deleted from
+  `node_modules` stayed deleted while bootstrap said it was complete. The
+  fresh-clone failure the issue reports did not reproduce.
+
 - 2026-10-06: A token symbol or name read off a contract is no longer stored cut
   between the two halves of an emoji
   ([#458](https://git.eeqj.de/sneak/AutistMask/issues/458)). `lookupTokenInfo()`