✨ Emit precompressed sidecars for served assets

Add scripts/precompress.ts, a dependency-free Node 26 tool that writes
.br/.gz/.zst sidecars next to every text asset and keeps the originals, so
static-web-server can serve the variant matching Accept-Encoding and fall
back to the original. The coverage publish step runs it on the copied report.

Wire scripts/*.ts into the toolchain: type-check (tsconfig include), lint and
fix (oxlint paths), knip entry (CI invokes the file rather than importing it),
and a narrow .oxlintrc override allowing node:* imports in Node CLI scripts.

tsconfig.json

@@ -8,5 +8,5 @@
         "allowImportingTsExtensions": true,
         "verbatimModuleSyntax": true
     },
-    "include": ["src"]
+    "include": ["src", "scripts"]
 }