Add Timelog: show the timer in the tab title and simplify the code

This is the first commit of the project, at the state that runs on
timelog.minhtrannhat.com.

Changes in this state:
- Remove redundant UI text from the sidebar, timer and insights pages.
- Show the remaining time and tag in the browser tab title while a
  session runs.
- Put the shared record type and the due and end helpers in
  src/shared/record.ts.
- Remove the startup tag migration and the one-time Forest import
  script. The live data does not need them.
- Remove unused CSS, Playwright ignore rules and duplicate helpers.
- Do not track Forest CSV exports, because they contain private data.

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

scripts/build.ts

@@ -0,0 +1,24 @@
+import { copyFile, mkdir, readFile, writeFile } from "node:fs/promises";
+
+await mkdir("dist/assets", { recursive: true });
+const result = await Bun.build({
+  entrypoints: ["src/client/main.ts"],
+  outdir: "dist/assets",
+  target: "browser",
+  minify: true,
+  naming: "app.js",
+});
+if (!result.success) {
+  for (const log of result.logs) console.error(log);
+  process.exit(1);
+}
+const buildId = Date.now().toString(36);
+const html = await readFile("src/client/index.html", "utf8");
+await writeFile("dist/index.html", html.replaceAll("__BUILD_ID__", buildId));
+await copyFile("src/client/styles.css", "dist/styles.css");
+await copyFile("src/client/manifest.webmanifest", "dist/manifest.webmanifest");
+await copyFile("src/client/icon.svg", "dist/icon.svg");
+for (const size of [180, 192, 512]) await copyFile(`src/client/icon-${size}.png`, `dist/icon-${size}.png`);
+const worker = await readFile("src/client/sw.js", "utf8");
+await writeFile("dist/sw.js", worker.replaceAll("__BUILD_ID__", buildId));
+console.log("Built PWA in dist/");