Initial commit — wiring diagram maker with full feature set

- FastAPI + SQLite backend with routers for diagrams, devices, wires,
  bundles, connectors, export, and Octopart/Nexar search
- Konva.js canvas: ortho/direct/curved routing, wire crossings, harness
  mode, snap-to-grid, multi-select, drag, resize, undo
- Wire features: color/stripe, twisted pair helix, shielded glow,
  gauge size label, multi-core bundle grouping, length/unit tracking
- Device library: connector, terminal block, cable, splice, label, group,
  relay, fuse, switch, component with custom connector support
- Exports: BOM CSV, assembly TXT, JSON, formboard layout, PNG image
- Auto-migration for schema changes via ALTER TABLE at startup

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

backend/app/schemas.py

@@ -0,0 +1,180 @@
+from pydantic import BaseModel, field_validator
+from typing import Optional, List, Any, Dict
+from datetime import datetime
+
+
+class DeviceBase(BaseModel):
+    device_type: str
+    label: str = ""
+    reference: str = ""
+    x: float = 100
+    y: float = 100
+    width: float = 120
+    height: float = 60
+    properties: Dict[str, Any] = {}
+    pins: List[Dict[str, Any]] = []
+
+
+class DeviceCreate(DeviceBase):
+    diagram_id: int
+
+
+class DeviceUpdate(BaseModel):
+    label: Optional[str] = None
+    reference: Optional[str] = None
+    x: Optional[float] = None
+    y: Optional[float] = None
+    width: Optional[float] = None
+    height: Optional[float] = None
+    properties: Optional[Dict[str, Any]] = None
+    pins: Optional[List[Dict[str, Any]]] = None
+
+
+class Device(DeviceBase):
+    id: int
+    diagram_id: int
+
+    model_config = {"from_attributes": True}
+
+
+class WireBase(BaseModel):
+    label: str = ""
+    from_device_id: Optional[int] = None
+    from_pin: str = ""
+    to_device_id: Optional[int] = None
+    to_pin: str = ""
+    color_primary: str = "#FF0000"
+    color_stripe: Optional[str] = None
+    gauge: str = "18 AWG"
+    length: Optional[float] = None
+    length_unit: str = "in"
+    notes: str = ""
+    waypoints: List[Dict[str, Any]] = []
+    twisted_pair: bool = False
+    twist_pitch: float = 16.0
+    shielded: bool = False
+    bundle_id: Optional[int] = None
+    show_size_label: bool = False
+
+    @field_validator("waypoints", mode="before")
+    @classmethod
+    def _coerce_waypoints(cls, v):
+        return v if v is not None else []
+
+
+class WireCreate(WireBase):
+    diagram_id: int
+
+
+class WireUpdate(BaseModel):
+    label: Optional[str] = None
+    from_device_id: Optional[int] = None
+    from_pin: Optional[str] = None
+    to_device_id: Optional[int] = None
+    to_pin: Optional[str] = None
+    color_primary: Optional[str] = None
+    color_stripe: Optional[str] = None
+    gauge: Optional[str] = None
+    length: Optional[float] = None
+    length_unit: Optional[str] = None
+    notes: Optional[str] = None
+    waypoints: Optional[List[Dict[str, Any]]] = None
+    twisted_pair: Optional[bool] = None
+    twist_pitch: Optional[float] = None
+    shielded: Optional[bool] = None
+    bundle_id: Optional[int] = None
+    show_size_label: Optional[bool] = None
+
+
+class Wire(WireBase):
+    id: int
+    diagram_id: int
+
+    model_config = {"from_attributes": True}
+
+
+# ── WireBundle ────────────────────────────────────────────────────────────────
+
+class WireBundleBase(BaseModel):
+    label: str = ""
+    jacket_color: str = "#2a2a2a"
+
+
+class WireBundleCreate(WireBundleBase):
+    diagram_id: int
+
+
+class WireBundleUpdate(BaseModel):
+    label: Optional[str] = None
+    jacket_color: Optional[str] = None
+
+
+class WireBundleOut(WireBundleBase):
+    id: int
+    diagram_id: int
+
+    model_config = {"from_attributes": True}
+
+
+# ── Diagram ───────────────────────────────────────────────────────────────────
+
+class DiagramBase(BaseModel):
+    name: str = "Untitled Diagram"
+    description: str = ""
+
+
+class DiagramCreate(DiagramBase):
+    pass
+
+
+class DiagramUpdate(BaseModel):
+    name: Optional[str] = None
+    description: Optional[str] = None
+
+
+class DiagramSummary(DiagramBase):
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class DiagramFull(DiagramSummary):
+    devices: List[Device] = []
+    wires: List[Wire] = []
+    wire_bundles: List[WireBundleOut] = []
+
+
+# ── CustomConnector ───────────────────────────────────────────────────────────
+
+class CustomConnectorBase(BaseModel):
+    name: str
+    manufacturer: str = ""
+    part_number: str = ""
+    category: str = "Custom"
+    description: str = ""
+    pin_count: int
+    pin_labels: List[str] = []
+
+
+class CustomConnectorCreate(CustomConnectorBase):
+    pass
+
+
+class CustomConnectorUpdate(BaseModel):
+    name: Optional[str] = None
+    manufacturer: Optional[str] = None
+    part_number: Optional[str] = None
+    category: Optional[str] = None
+    description: Optional[str] = None
+    pin_count: Optional[int] = None
+    pin_labels: Optional[List[str]] = None
+
+
+class CustomConnector(CustomConnectorBase):
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    model_config = {"from_attributes": True}