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]>

src/client/sync.ts

@@ -0,0 +1,58 @@
+import type { TimeRecord } from "../shared/record.ts";
+import { allRecords, applyRemote, cursor, pendingOperations, removeOperations } from "./store.ts";
+
+export type SyncStatus = "offline" | "syncing" | "synced" | "pending" | "signed-out";
+let current: Promise<void> | null = null;
+let rerunRequested = false;
+
+class SignedOut extends Error {}
+
+async function api<T>(url: string, init?: RequestInit): Promise<T> {
+  const response = await fetch(url, init);
+  if (response.status === 401) throw new SignedOut();
+  if (!response.ok) throw new Error(`Sync failed (${response.status})`);
+  return response.json() as Promise<T>;
+}
+
+export function syncNow(onChange: (status: SyncStatus, records?: TimeRecord[]) => void): Promise<void> {
+  if (current) {
+    rerunRequested = true;
+    return current;
+  }
+  current = (async () => {
+    if (!navigator.onLine) { onChange("offline"); return; }
+    onChange("syncing");
+    try {
+      let pending = await pendingOperations();
+      while (pending.length) {
+        const batch = pending.slice(0, 200);
+        const body = await api<{ accepted: string[] }>("/api/operations", {
+          method: "POST", headers: { "Content-Type": "application/json" },
+          body: JSON.stringify({ operations: batch.map(({ id, record }) => ({ id, record })) }),
+        });
+        await removeOperations(body.accepted);
+        pending = await pendingOperations();
+      }
+      let since = await cursor();
+      for (;;) {
+        const body = await api<{ records: TimeRecord[]; cursor: number; hasMore: boolean }>(
+          `/api/state?since=${since}`, { cache: "no-store" });
+        await applyRemote(body.records, body.cursor);
+        since = body.cursor;
+        if (!body.hasMore) break;
+      }
+      onChange("synced", await allRecords());
+    } catch (error) {
+      if (error instanceof SignedOut) { onChange("signed-out"); return; }
+      console.error(error);
+      onChange("pending");
+    }
+  })().finally(() => {
+    current = null;
+    if (rerunRequested) {
+      rerunRequested = false;
+      void syncNow(onChange);
+    }
+  });
+  return current;
+}