Refactor capture engine architecture, rename PictureStream to PictureSource, and split API modules

- Separate CaptureEngine into stateless factory + stateful CaptureStream session
- Add LiveStream/LiveStreamManager for shared capture with reference counting
- Rename PictureStream to PictureSource across storage, API, and UI
- Remove legacy migration logic and unused compatibility code
- Split monolithic routes.py (1935 lines) into 5 focused route modules
- Split schemas.py (480 lines) into 7 schema modules with re-exports
- Extract dependency injection into dedicated dependencies.py

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/api/schemas/picture_sources.py

@@ -0,0 +1,80 @@
+"""Picture source schemas."""
+
+from datetime import datetime
+from typing import List, Literal, Optional
+
+from pydantic import BaseModel, Field
+
+
+class PictureSourceCreate(BaseModel):
+    """Request to create a picture source."""
+
+    name: str = Field(description="Stream name", min_length=1, max_length=100)
+    stream_type: Literal["raw", "processed", "static_image"] = Field(description="Stream type")
+    display_index: Optional[int] = Field(None, description="Display index (raw streams)", ge=0)
+    capture_template_id: Optional[str] = Field(None, description="Capture template ID (raw streams)")
+    target_fps: Optional[int] = Field(None, description="Target FPS (raw streams)", ge=10, le=90)
+    source_stream_id: Optional[str] = Field(None, description="Source stream ID (processed streams)")
+    postprocessing_template_id: Optional[str] = Field(None, description="Postprocessing template ID (processed streams)")
+    image_source: Optional[str] = Field(None, description="Image URL or file path (static_image streams)")
+    description: Optional[str] = Field(None, description="Stream description", max_length=500)
+
+
+class PictureSourceUpdate(BaseModel):
+    """Request to update a picture source."""
+
+    name: Optional[str] = Field(None, description="Stream name", min_length=1, max_length=100)
+    display_index: Optional[int] = Field(None, description="Display index (raw streams)", ge=0)
+    capture_template_id: Optional[str] = Field(None, description="Capture template ID (raw streams)")
+    target_fps: Optional[int] = Field(None, description="Target FPS (raw streams)", ge=10, le=90)
+    source_stream_id: Optional[str] = Field(None, description="Source stream ID (processed streams)")
+    postprocessing_template_id: Optional[str] = Field(None, description="Postprocessing template ID (processed streams)")
+    image_source: Optional[str] = Field(None, description="Image URL or file path (static_image streams)")
+    description: Optional[str] = Field(None, description="Stream description", max_length=500)
+
+
+class PictureSourceResponse(BaseModel):
+    """Picture source information response."""
+
+    id: str = Field(description="Stream ID")
+    name: str = Field(description="Stream name")
+    stream_type: str = Field(description="Stream type (raw, processed, or static_image)")
+    display_index: Optional[int] = Field(None, description="Display index")
+    capture_template_id: Optional[str] = Field(None, description="Capture template ID")
+    target_fps: Optional[int] = Field(None, description="Target FPS")
+    source_stream_id: Optional[str] = Field(None, description="Source stream ID")
+    postprocessing_template_id: Optional[str] = Field(None, description="Postprocessing template ID")
+    image_source: Optional[str] = Field(None, description="Image URL or file path")
+    created_at: datetime = Field(description="Creation timestamp")
+    updated_at: datetime = Field(description="Last update timestamp")
+    description: Optional[str] = Field(None, description="Stream description")
+
+
+class PictureSourceListResponse(BaseModel):
+    """List of picture sources response."""
+
+    streams: List[PictureSourceResponse] = Field(description="List of picture sources")
+    count: int = Field(description="Number of streams")
+
+
+class PictureSourceTestRequest(BaseModel):
+    """Request to test a picture source."""
+
+    capture_duration: float = Field(default=5.0, ge=1.0, le=30.0, description="Duration to capture in seconds")
+    border_width: int = Field(default=10, ge=1, le=100, description="Border width in pixels for preview")
+
+
+class ImageValidateRequest(BaseModel):
+    """Request to validate an image source (URL or file path)."""
+
+    image_source: str = Field(description="Image URL or local file path")
+
+
+class ImageValidateResponse(BaseModel):
+    """Response from image validation."""
+
+    valid: bool = Field(description="Whether the image source is accessible and valid")
+    width: Optional[int] = Field(None, description="Image width in pixels")
+    height: Optional[int] = Field(None, description="Image height in pixels")
+    preview: Optional[str] = Field(None, description="Base64-encoded JPEG thumbnail")
+    error: Optional[str] = Field(None, description="Error message if invalid")