# Composite Nesting Support

## Phase 1: Store — Cycle & Depth Validation

- [x] Add `get_transitive_dependencies()` to ColorStripStore
- [x] Add `validate_nesting()` with cycle detection + depth limit (MAX_DEPTH=4)

## Phase 2: API — Validation in Create/Update

- [x] Call `validate_nesting()` in create handler for composite sources
- [x] Call `validate_nesting()` in update handler for composite sources

## Phase 3: Runtime — Depth Guard in Stream

- [x] Add `depth` parameter to CompositeColorStripStream
- [x] Pass depth through ColorStripStreamManager.acquire()
- [x] Cap depth at runtime to prevent runaway nesting

## Phase 4: Frontend — Allow Composites in Layer Dropdown

- [x] Remove `source_type !== 'composite'` filter (keep self-exclusion)
- [x] Update docstring in composite_stream.py

## Phase 5: Tests

- [x] Cycle detection tests (A→B→A, self-reference)
- [x] Depth limit tests (chain exceeding MAX_DEPTH)
- [x] Valid nesting tests (A→B both composite, no cycle)

## Phase 6: Lint & Build

- [x] Ruff check passes
- [x] TypeScript build passes
- [x] All existing tests pass (715/715)