# `muse reflog` — use long IDs in human text output

## Problem

`_fmt_entry` in `muse/cli/commands/reflog.py` renders commit IDs using `short_id`
(12 hex chars) in the human text output:

```python
def _fmt_entry(idx: int, entry: ReflogEntry, short: int = 12) -> str:
    new_short = sanitize_display(short_id(entry.new_id))
    old_short = (
        "initial"
        if entry.old_id == NULL_COMMIT_ID
        else sanitize_display(short_id(entry.old_id))
    )
```

This produces output like:

```
@{0} sha256:3f9a1c2d4e7b  (sha256:9b2e4a1f8c3d)  2026-06-28 14:22:11 UTC  claude-code  fix: off-by-one in total
```

Every other Muse command that surfaces a commit ID in human text uses `long_id` —
the canonical `sha256:<64-hex>` form. The reflog is inconsistent and the IDs it
displays cannot be passed directly to other commands without risk of prefix collision.

The docstring even contradicts itself: it claims short IDs are used "for consistency
with all other Muse commands" when the opposite is true.

Additionally, the `short: int = 12` parameter in `_fmt_entry` is declared but never
referenced in the function body — dead parameter, should be removed.

The JSON output layer already uses `long_id` correctly via `_ReflogEntryJson`. Only
the human text path needs fixing.

## Fix

In `muse/cli/commands/reflog.py`:

1. Replace both `short_id(...)` calls in `_fmt_entry` with `long_id(...)`.
2. Remove the unused `short: int = 12` parameter.
3. Update the docstring to reflect that full IDs are rendered.
4. Update the format spec comment string at the top of `run()` docstring
   (`<new_sha12>` → `<new_sha256>`).

Correct output after the fix:

```
@{0} sha256:3f9a1c2d4e7b9c2a4f1d8e3b6c9f2d1a7e4b8c1f5a9d2e6b3c7f0a4d1e8b2c5f  (sha256:9b2e4a1f8c3d7b4e2c1a5f9d3e7b2c8f1a4e7b3c9f2a6d1e4b8c3f7a0d2e5b98)  2026-06-28 14:22:11 UTC  claude-code  fix: off-by-one in total
```

## Deliverables

- [ ] `LI_01` — `_fmt_entry` uses `long_id` for `new_id`; output is `sha256:<64-hex>`
- [ ] `LI_02` — `_fmt_entry` uses `long_id` for `old_id`; `"initial"` sentinel unchanged
- [ ] `LI_03` — Unused `short: int = 12` parameter removed from `_fmt_entry` signature
- [ ] `LI_04` — `_fmt_entry` docstring updated; no stale reference to short IDs or the
  false "consistency" claim
- [ ] `LI_05` — `run()` docstring format spec updated to reflect full IDs
- [ ] `LI_06` — Test: `muse reflog` human text output contains the full 64-hex commit ID
  of the most recent entry, not a 12-char prefix

**Test file:** `tests/test_cmd_reflog_long_ids.py`

## Out of scope

- JSON output — already correct (`long_id` used in `_ReflogEntryJson`).
- Any other command's ID rendering.