fix(ui): move repo-stats Observed timeago under physical bytes

It belongs to the kopia-reported inspection figures, not the bucket
figure. The bucket-bytes tooltip now carries its own CloudWatch
measurement time and notes the once-a-day cadence.

Author: passcod

private-web/e2e/backups.spec.ts

@@ -289,6 +289,18 @@ test.describe("backups ready: stats + backup-now", () => {
 		await expect(page.getByText("42")).toBeVisible();
 		// bucket_bytes NULL → "unknown" shown, per the indicators rule.
 		await expect(page.getByText(/bucket bytes:\s*unknown/i)).toBeVisible();
+		// The "Observed" timestamp belongs to the kopia-reported repo stats, so
+		// it sits under "Physical bytes", above the bucket figure.
+		const statsPanel = page
+			.getByRole("heading", { name: /repository stats/i })
+			.locator("..");
+		const panelText = await statsPanel.innerText();
+		expect(panelText.indexOf("Observed")).toBeGreaterThan(
+			panelText.indexOf("Physical bytes"),
+		);
+		expect(panelText.indexOf("Observed")).toBeLessThan(
+			panelText.indexOf("Bucket bytes"),
+		);
 		await expect(page.getByText(/recent runs/i)).toBeVisible();
 		await expect(page.getByText("success")).toBeVisible();
 		// The run carries a server_id, so the table names which server it's from.
@@ -436,6 +448,7 @@ test.describe("backups ready: stats + backup-now", () => {
 		await seedBackupRepoStats(sql, {
 			groupId: group.id,
 			bucketBytes: 107374182400, // 100 GiB
+			bucketBytesObservedAt: new Date(Date.now() - 86_400_000).toISOString(),
 		});
 
 		await page.goto(`/groups/${group.id}/backups`);
@@ -445,6 +458,12 @@ test.describe("backups ready: stats + backup-now", () => {
 		const tooltip = page.getByRole("tooltip");
 		await expect(tooltip).toContainText("$2.50/month");
 		await expect(tooltip).toContainText("ap-southeast-2");
+		// The bucket figure comes from CloudWatch on its own daily cadence, so
+		// the tooltip carries its measurement time and says it updates less
+		// often than the kopia-reported stats.
+		await expect(tooltip).toContainText("From CloudWatch storage metrics");
+		await expect(tooltip).toContainText("measured");
+		await expect(tooltip).toContainText("about once a day");
 	});
 
 	test("recent run shows a truncated, copyable snapshot id", async ({

private-web/e2e/seed.ts

@@ -562,19 +562,22 @@ export async function seedBackupRepoStats(
 		logicalBytes?: number | null;
 		physicalBytes?: number | null;
 		bucketBytes?: number | null;
+		/** ISO timestamp of the bucket-bytes measurement. */
+		bucketBytesObservedAt?: string | null;
 	},
 ): Promise<void> {
 	await sql.query(
 		`INSERT INTO backup_repo_stats
-		 (group_id, snapshot_count, source_count, logical_bytes, physical_bytes, bucket_bytes)
-		 VALUES ($1, $2, $3, $4, $5, $6)`,
+		 (group_id, snapshot_count, source_count, logical_bytes, physical_bytes, bucket_bytes, bucket_bytes_observed_at)
+		 VALUES ($1, $2, $3, $4, $5, $6, $7)`,
 		[
 			opts.groupId,
 			opts.snapshotCount ?? null,
 			opts.sourceCount ?? null,
 			opts.logicalBytes ?? null,
 			opts.physicalBytes ?? null,
 			opts.bucketBytes ?? null,
+			opts.bucketBytesObservedAt ?? null,
 		],
 	);
 }