Add printer types with bed volume + add-printer UI

- PrinterType model: name, bed_x_mm/y/z, linked to Printer via type_id
- Migration 0002: creates printer_types, adds type_id to printers, drops model
- /printer-types page: table + Add Type modal form
- /printers page: Add Printer modal with type dropdown (disabled if no types)
- API: GET/POST/DELETE /api/printer-types

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

app/models/printer.py

@@ -1,7 +1,7 @@
 import enum
 from datetime import datetime
 
-from sqlalchemy import DateTime, Enum, String, func
+from sqlalchemy import DateTime, Enum, ForeignKey, String, func
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
 from app.models.base import Base
@@ -19,8 +19,8 @@ class Printer(Base):
 
     id: Mapped[int] = mapped_column(primary_key=True)
     name: Mapped[str] = mapped_column(String(100))
-    model: Mapped[str | None] = mapped_column(String(100))
     location: Mapped[str | None] = mapped_column(String(100))
+    type_id: Mapped[int | None] = mapped_column(ForeignKey("printer_types.id"))
     status: Mapped[PrinterStatus] = mapped_column(
         Enum(PrinterStatus), default=PrinterStatus.offline
     )
@@ -29,5 +29,6 @@ class Printer(Base):
         DateTime, server_default=func.now(), onupdate=func.now()
     )
 
+    printer_type: Mapped["PrinterType | None"] = relationship(back_populates="printers")
     jobs: Mapped[list["PrintJob"]] = relationship(back_populates="printer")
     todos: Mapped[list["Todo"]] = relationship(back_populates="printer")