✨ 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.

.oxlintrc.json

@@ -33,6 +33,12 @@
                 "import/no-nodejs-modules": "off",
                 "eslint/no-magic-numbers": "off"
             }
+        },
+        {
+            "files": ["scripts/**/*.ts"],
+            "rules": {
+                "import/no-nodejs-modules": "off"
+            }
         }
     ],
     "ignorePatterns": ["dist", "node_modules", "coverage"]