CloudQueryError prevents /chronicle standup despite local fallback data

### Describe the bug

## Summary

`/chronicle standup` fails when the cloud session store returns `CloudQueryError: internal server error`.

Local session data is available, and some `session_store_sql` queries successfully return local fallback rows. However, the DuckDB-style timestamp predicates used for last-24-hours chronicle queries appear to prevent local fallback from rescuing the command.

## Environment

- GitHub Copilot CLI: `1.0.64`
- Platform: Windows
- Package metadata: `@github/copilot` `1.0.64`, build metadata `ae586e7`
- Startup log showed: `No update needed, current version is 1.0.64, fetched latest release is v1.0.64`

## Impact

`/chronicle standup` cannot generate a standup report even though recent local session rows are available.

## Expected behavior

When the cloud session store fails with an internal server error, `session_store_sql` and `/chronicle standup` should degrade gracefully to local indexed sessions where possible, returning local rows with a warning.

## Actual behavior

The required last-24-hours query fails with:

```text
CloudQueryError: {"documentation_url":"https://docs.github.com/rest","message":"internal server error"}
```

### Affected version

1.0.64

### Steps to reproduce the behavior

This query fails completely:

SELECT id, branch, updated_at
FROM sessions
WHERE updated_at >= TIMESTAMP '2026-06-23T07:47:34.106Z'
ORDER BY updated_at DESC
LIMIT 5

This also failed:

SELECT id, branch, updated_at
FROM sessions
WHERE updated_at >= now() - INTERVAL '1 day'
ORDER BY updated_at DESC
LIMIT 5

But this query returns local fallback rows:

SELECT id, branch, updated_at
FROM sessions
ORDER BY updated_at DESC
LIMIT 5

Observed fallback behavior:

5 row(s) returned from _query_source = local
Cloud query failed (CloudQueryError: {"documentation_url":"https://docs.github.com/rest","message":"internal server error"}). Showing local results only.

### Expected behavior

_No response_

### Additional context

_No response_

Bắt đầu với phần xử lý session_store_sql và đường dẫn truy vấn /chronicle standup. Tái hiện các truy vấn được lọc theo dấu thời gian và so sánh chúng với truy vấn fallback cục bộ không được lọc; hoàn tất khi /chronicle standup trả về các session được lập chỉ mục cục bộ kèm cảnh báo khi truy vấn cloud thất bại.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.