fix(viewer): handle multiple timestamp formats in days calculation

[abakane1]

Description

• Support milliseconds, microseconds, and seconds timestamp formats in days calculation
• Fixes incorrect days calculation (showing 36500 days) when timestamps use different formats

Changes

Modified apps/memos-local-openclaw/src/viewer/html.ts:

// Before: only handled milliseconds
if(e<1e12) e*=1000;

// After: handles all timestamp formats
if (e < 1e15 && e >= 1e12) e = Math.floor(e / 1000);  // microseconds to milliseconds
else if (e < 1e12) e *= 1000;  // seconds to milliseconds

Related Issue

N/A (found during local testing)

[hijzy]

Thanks for the PR — the direction is good, but the timestamp boundary logic needs adjustment.
Current logic treats 1e12 ~ 1e15 as microseconds and divides by 1000, which incorrectly affects millisecond timestamps.

Counterexample: 1700000000000 (milliseconds) becomes 1700000000 (seconds), i.e. wrong unit downscaling.

Please normalize to milliseconds as:

• ts >= 1e15 : microseconds → Math.floor(ts / 1000)
• 1e12 <= ts < 1e15 : milliseconds → keep as-is
• ts < 1e12 : seconds → ts * 1000
  Please also add a minimal test covering seconds/milliseconds/microseconds to prevent regressions. Thanks!

感谢提交！方向是对的，但时间戳区间判断还需要调整。
你现在把 1e12 ~ 1e15 当作微秒并除以 1000，这会误伤毫秒时间戳。

反例： 1700000000000 （毫秒）会被除成 1700000000 （秒），单位被错误降级。

请改为先统一到毫秒：

• ts >= 1e15 ：微秒 → Math.floor(ts / 1000)
• 1e12 <= ts < 1e15 ：毫秒 → 保持不变
• ts < 1e12 ：秒 → ts * 1000

另外请补一个最小测试覆盖 seconds/milliseconds/microseconds，避免回归。谢谢！