Background

PR #12 (`anvil epic` subcommand + `–epic` / `–parent` flags) gave the CLI baseline epic support. Once that lands, several follow-ups are needed for the CLI to feel as first-class as the web UI for epics. This is the umbrella ticket; we’ll split into sub-tickets as scope firms up.

Companion to fangorn/anvil#118 (epics epic, server-side).

Likely follow-ups

Discovery / browsing

• `anvil board`: render epic swimlanes when `–group-by epic` is passed. Today the board is a flat list per column; epic-aware grouping needs the same affordance the web board gets in fangorn/anvil#110.
• `anvil epic plan` — kanban-shaped view of just epics, mirror of the dedicated /epics page in fangorn/anvil#111.
• `anvil issue list –filter “is:epic epic:#107”` — wire the new filter DSL operators (already supported server-side after fangorn/anvil#113) into the CLI’s filter pass-through.

Mutations

• `anvil issue move` (covered by fangorn/anvil#8) — extend to handle epic-as-card moves when an epic-only board exists.
• `anvil epic close` / `anvil epic reopen` — convenience aliases that explicitly check the epic’s open-children policy and warn if there are still open children (mirrors PR-side warning from fangorn/anvil#115).
• `anvil pr create –epic <#>` or PR body resolver: surface “(part of Epic #N)” in the CLI when creating a PR that closes an issue with a parent epic.

Output formatting

• `anvil issue view <#>` for an epic should print the children table inline (today only `anvil epic view` does that).
• `anvil epic view` should color rows by state and group open vs closed (today single table).

Tests

• Mock-server integration tests (Wiremock-style) for the epic subcommand round-trips, since the current tests are unit tests of helpers only.

Sequencing

Wait for #12 and fangorn/anvil#118 children to land before filing sub-tickets — the API surface and UI conventions there will dictate the CLI shape.