## Context

The Planka v2 API `GET /api/boards/:id` response includes an `included` object with: `users`, `boardMemberships`, `labels`, `lists`, `cards`, `cardMemberships`, `cardLabels`, `taskLists`, `tasks`, `attachments`, `customFieldGroups`, `customFields`, `customFieldValues`. Currently `GetBoard` only parses `lists` and `cards`, discarding everything else.

The `CardLabel` and `Label` types already exist in `model/types.go`. The `Board` struct has `Lists` and `Cards` fields but not `Labels`, `CardLabels`, or `CardMemberships`.

## Goals / Non-Goals

**Goals:**
- Parse `labels`, `cardLabels`, and `cardMemberships` from the `GetBoard` response
- Make label data available on the `Board` struct for downstream consumers
- Enrich `ListCardsByBoard` output so `card list --board` includes label names per card

**Non-Goals:**
- Parsing all included fields (users, taskLists, attachments, customFields, etc.) — only what's needed now
- Adding label data to `card list --list` (uses a different API endpoint that doesn't include labels)
- Changing the `card get` response (already returns card-level data via a different endpoint)

## Decisions

### Add fields to Board struct rather than creating a separate BoardDetail type
**Decision**: Add `Labels`, `CardLabels`, and `CardMemberships` as optional fields on the existing `Board` struct with `omitempty`.

**Alternative**: Create a `BoardDetail` struct for the enriched response. Rejected — the fields are simply absent when not fetched (e.g., `ListBoards`), and `omitempty` handles this cleanly without a type split.

### Add Labels field to CardWithList for card list --board output
**Decision**: Add a `Labels` field (`[]string` of label names) to the `CardWithList` struct. `ListCardsByBoard` will resolve card→label associations via the `cardLabels` join table and `labels` list from the board response.

**Alternative**: Return full `Label` objects per card. Rejected — label names are sufficient for display and filtering; full objects add noise to output.

### Use join-table approach matching the API structure
**Decision**: Keep `CardLabel` as the join entity (cardId + labelId), and resolve to label names at the point of use (in `ListCardsByBoard`). This mirrors the Planka API's relational structure.

## Risks / Trade-offs

- **[Additive JSON fields]** → `card list --board` output will include a new `labels` array per card. Existing consumers that don't use this field are unaffected. Scripts using strict JSON parsing may need updating.
- **[Partial included parsing]** → We still skip users, taskLists, attachments, etc. This is intentional — parse only what's needed. Future changes can add more fields incrementally.