## ADDED Requirements

### Requirement: Camera prim selectable by clicking its wireframe
The system SHALL test each viewport left-mouse-button click against all camera wireframe segments before running the existing geometry pick. If the click position is within 10 screen pixels of any projected wireframe edge, the corresponding `UsdGeomCamera` prim SHALL be selected. Among multiple qualifying cameras the nearest one (smallest minimum screen distance) SHALL be chosen.

#### Scenario: Clicking camera wireframe selects the camera prim
- **WHEN** the user left-clicks within 10 pixels of a camera wireframe segment
- **THEN** the camera prim appears selected in the Scene Hierarchy panel and the Property panel shows its attributes

#### Scenario: Camera pick takes priority over geometry behind it
- **WHEN** the user clicks on a camera wireframe that visually overlaps rendered geometry
- **THEN** the camera prim is selected, not the geometry behind it

#### Scenario: Click misses all cameras — falls through to geometry pick
- **WHEN** the user left-clicks on an area with no camera wireframe within 10 pixels
- **THEN** the normal geometry pick runs as before

### Requirement: Selected camera is editable with the transform manipulator
After a camera prim is selected via viewport click, the system SHALL allow the `TransformManipulator` to translate and rotate it using the existing W/E/R tool modes. The camera SHALL implement `UsdGeomXformCommonAPI` for the manipulator to write to. No additional manipulator changes are required.

#### Scenario: Move manipulator repositions selected camera
- **WHEN** a camera prim is selected and the Move tool (W) is active
- **THEN** the translate gizmo appears at the camera's world position and dragging it moves the camera prim

#### Scenario: Rotate manipulator reorients selected camera
- **WHEN** a camera prim is selected and the Rotate tool (E) is active
- **THEN** the rotate rings appear at the camera's world position and dragging them rotates the camera prim
