feat(wsh): add 'tab list' and 'tab move' commands for scriptable tab management (#3426)

## Summary

This PR adds two new wsh subcommands under `wsh tab` to make tabs
scriptable from the command line, addressing #3425.

### New commands

**`wsh tab list`** (alias: `ls`) — lists tabs in the current workspace
with their ids, names, and indices.
- Defaults to the current workspace from `WAVETERM_WORKSPACEID`,
overridable with `--workspace <id>`
- Supports `--json` flag for machine-readable output
- Example:
  ```
  $ wsh tab list
  INDEX  TAB ID                                NAME
  0      550e8400-e29b-41d4-a716-446655440000  Terminal
  1      650e8400-e29b-41d4-a716-446655440001  google.com
  ```

**`wsh tab move <tabid> --index <n>`** — moves a tab to the specified
0-based position within its workspace.
- Validates that the tab exists in the workspace and that the index is
in range
- Guards against dropping/adding tabs (the set of tab ids is preserved
exactly)
- No-op when the tab is already at the target index
- Example:
  ```
  $ wsh tab move 650e8400-e29b-41d4-a716-446655440001 --index 0
  moved tab 650e8400-... from index 1 to 0
  ```

### Bug fix
- Fixed a small bug in `wsh workspace list` where the `workspaceId`
field was being printed to stderr instead of stdout due to a
`WriteStderr`/`WriteStdout` typo.

### Testing
- Added unit tests for the tab reordering logic (`reorderTabIds`)
covering 8 scenarios: first↔last, left/right moves, adjacent swaps, and
two-element arrays
- All existing tests in `cmd/wsh/cmd/` continue to pass
- `go build ./cmd/wsh/...` and `go vet ./cmd/wsh/...` clean
- `gofmt` verified

Closes #3425