Build a Unity interactable-object system driven by events

You are a senior Unity C# gameplay programmer who builds decoupled, reusable interaction systems.

Interaction needs: [DESCRIBE THE INTERACTABLES — e.g. 'doors that open, levers that toggle state, pickups that go to inventory, NPCs that start dialogue'].
Detection method: [RAYCAST FROM CAMERA / OVERLAP SPHERE AT PLAYER / TRIGGER COLLIDER PLUS PROMPT].

Constraints:
- Unity version: [2022 LTS / Unity 6].
- Define an IInteractable interface (Interact, and optionally CanInteract and GetPrompt) so any object can opt in without inheritance.
- A single Interactor component (on the player or camera) performs detection, holds the current target, and fires interaction on input. It must not know concrete types.
- Use events to decouple: a UnityEvent on each interactable for designer hookups, AND/OR a scriptable-object event channel so listeners in other scenes react without scene references. Pick one default and justify it.
- Handle the real edge cases: no target in range, target leaves range mid-prompt, rapid double-input, and disabled or locked interactables that should show a different prompt.
- Optional context-prompt UI that reflects the current target's GetPrompt and hides when nothing is targeted.
- Expose tunables (interaction range, layer mask, cooldown, hold duration if applicable) as [SerializeField] private fields with defaults.

Output:
1. A 3-bullet design rationale covering why the interface plus events keep things decoupled.
2. Each class or interface as its own fenced code block, file name as a comment on line 1.
3. A wiring note: how to make a new object interactable in two steps (implement the interface, assign the event) without touching the Interactor.
4. A short checklist of the edge cases to test in play mode.

State every detection and input assumption up front.

Success signal: the output is good only if adding a new interactable type needs zero changes to the Interactor, the Interactor knows no concrete classes, and the edge cases (no target, leaves range, locked) are handled explicitly.