feat: add label commands (task 0015)

.claude/tasks/0015-label-commands.md

@@ -13,10 +13,28 @@ The label command group: `label list`, `label create`, `label edit`, `label dele
 
 ## Acceptance criteria
 
-- [ ] `label list` renders the count line and `labels:` block; empty repos get the explicit empty state
-- [ ] `label create --name --color` creates the label, prepending `#` to the color, and outputs `created: ok` + `label: <name>`
-- [ ] Creating an existing label (case-insensitive) outputs `create: already_exists` + the existing name, exit 0
-- [ ] `label edit <name>` applies `--name`/`--color`/`--description` and outputs `edit: ok` + the resulting name
-- [ ] `label edit`/`label delete` on an unknown name yield `VALIDATION_ERROR` (exit 2)
-- [ ] `label delete <name>` outputs `delete: ok` + `label: <name>`
-- [ ] Fixture-server tests cover create, idempotent re-create, edit, delete, and the unknown-name refusals
+- [x] `label list` renders the count line and `labels:` block; empty repos get the explicit empty state
+- [x] `label create --name --color` creates the label, prepending `#` to the color, and outputs `created: ok` + `label: <name>`
+- [x] Creating an existing label (case-insensitive) outputs `create: already_exists` + the existing name, exit 0
+- [x] `label edit <name>` applies `--name`/`--color`/`--description` and outputs `edit: ok` + the resulting name
+- [x] `label edit`/`label delete` on an unknown name yield `VALIDATION_ERROR` (exit 2)
+- [x] `label delete <name>` outputs `delete: ok` + `label: <name>`
+- [x] Fixture-server tests cover create, idempotent re-create, edit, delete, and the unknown-name refusals
+
+## Implementation Notes
+
+Built the `label` group in `src/commands/label.ts`, wired into `src/cli.ts` (dispatcher plus the two most-common entries in the top-level help), following the sibling `issue`/`pr` command patterns.
+
+Deviations and decisions:
+
+- **`label edit` requires at least one change.**
+The spec/gh-axi reference leaves all edit flags optional, but sending an empty `PATCH` is a pointless call, so an edit with none of `--name`/`--color`/`--description` is refused with `VALIDATION_ERROR` — mirroring `issue edit`'s "requires at least one change" guard for consistency within gitea-axi.
+- **Resulting name for `edit`/`create`/`delete` comes from the API response** (`edited.name`, `label.name`), not the input, so the reported name is the server's canonical echo (correct casing, and the unchanged original when `--name` was omitted).
+- **`create` vs `created` output keys.**
+The success key is `created: ok` and the idempotent-hit key is `create: already_exists` — two different top-level keys.
+This is spec-mandated (spec lines 342–343) rather than the `already: true` shape the dependency no-ops use; kept verbatim to match the fixed contract.
+- **Flat `renderObject` output shape.**
+Added `renderObject(item, help)` to `src/render.ts` because the label create/edit/delete outputs are flat top-level fields (`created: ok` / `label: <name>`), which the sibling `renderDetail` (nests under a `noun:` block) cannot produce. This is the spec's output shape, not a new convention chosen freely.
+- **Shared lookup + positional helpers (cleanups from review).**
+Extracted `findLabel`/`resolveLabel` and a shared `labelNotFound` message into `src/lookup.ts`, reused by the existing `resolveLabelIds`; and extracted `parseSinglePositional` in `src/flags.ts`, now shared by `parsePositionalNumber` and the label name positionals, removing the duplicated count-check/error scaffolding.
+- **`label list` uses a single-page fetch with `--limit` (default 500)**, reading `X-Total-Count` for the count line, rather than the exhaustive pagination `resolveLabel`/`resolveLabelIds` use; the spec asks only for `--limit`, and a repo with >500 labels is signalled by the `count: N of T total` line.