Make pages load fast on mobile

- Compress responses: page scripts and styles once (brotli or gzip, in
  memory) and cached immutable; pages and API JSON gzipped as they stream
- Service worker serves content-named assets cache-first
- Load the models modal's data when it opens (cached in localStorage)
  instead of shipping the model catalog in every conversation page
- Lazy-load the Tiptap composer and memoize thread messages
- Import lucide icons directly; twui 0.1.4 drops by-name icons from Button
- bun run start builds the pages minified before serving

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/utils/pick-content-encoding.test.ts

@@ -0,0 +1,29 @@
+import { describe, expect, test } from "bun:test";
+import pickContentEncoding from "./pick-content-encoding";
+
+describe("pickContentEncoding", () => {
+    test("prefers brotli", () => {
+        expect(pickContentEncoding({ accept_encoding: "gzip, deflate, br, zstd" })).toBe("br");
+    });
+
+    test("falls back to gzip", () => {
+        expect(pickContentEncoding({ accept_encoding: "gzip, deflate" })).toBe("gzip");
+        expect(pickContentEncoding({ accept_encoding: "*", offer: ["gzip"] })).toBe("gzip");
+    });
+
+    test("only offers what the caller can produce", () => {
+        expect(pickContentEncoding({ accept_encoding: "br, gzip", offer: ["gzip"] })).toBe("gzip");
+        expect(pickContentEncoding({ accept_encoding: "br", offer: ["gzip"] })).toBe(null);
+    });
+
+    test("is none without a supported coding", () => {
+        expect(pickContentEncoding({ accept_encoding: "identity" })).toBe(null);
+        expect(pickContentEncoding({ accept_encoding: "" })).toBe(null);
+        expect(pickContentEncoding({ accept_encoding: null })).toBe(null);
+    });
+
+    test("skips refused codings", () => {
+        expect(pickContentEncoding({ accept_encoding: "br;q=0, gzip;q=0.8" })).toBe("gzip");
+        expect(pickContentEncoding({ accept_encoding: "br;q=0.0, gzip;q=0" })).toBe(null);
+    });
+});