Problem

`anvil epic list` takes the repo as a positional argument:

``` $ anvil epic list –repo fangorn/anvil error: unexpected argument ‘–repo’ found $ anvil epic list fangorn/anvil # works ```

This matches the existing `anvil issue list` / `anvil pr list` style (positional `[REPO]`), so it is internally consistent with other `*list` commands.

However, every other epic subcommand (`view`, `children`, `add-child`, `remove-child`, `mark`, `auto-close`) uses `–repo `. After running e.g. `anvil epic view 118 –repo fangorn/anvil`, reaching for `–repo` on `epic list` is a natural mistake.

Proposed fix

Accept BOTH on `*list` commands: keep the positional for backwards-compat, but also accept `–repo`. If both are provided, prefer `–repo` (or error). This is purely additive — no existing usage breaks.

Probably the cleanest approach is the same on `issue list` and `pr list` so all three list commands behave uniformly with the rest of the CLI.

Acceptance criteria

• `anvil epic list –repo fangorn/anvil` works
• `anvil epic list fangorn/anvil` still works (positional preserved)
• Same applies to `issue list` and `pr list`
• Help text shows both forms

Priority

Low. Cosmetic. File-and-forget.