Replace Canvas Attribute Injection with React Context

[forestileao]

Problem
The current implementation relies on deeply injecting Canvas-related attributes from workflowv2/index → CanvasPage → downstream internal components. This creates tight coupling, makes the component tree harder to reason about, and contributes to unnecessary re-renders.

Proposed Solution
Replace prop-based deep injection with React Context.

• Introduce context(s) using [createContext](https://react.dev/reference/react/createContext) to provide Canvas-related data.
• Define interfaces within src/ui that consume these contexts without performing HTTP requests.
• Keep src/ui purely declarative and framework-driven.
• Move the actual implementations (including any side effects or HTTP logic) outside src/ui, where they can use any required dependencies.

Benefits

• Reduces prop drilling and improves component encapsulation
• Minimizes unnecessary re-renders
• Simplifies development and improves maintainability
• Creates a clearer separation between UI contracts and implementation details

Notes

• Ensure contexts are scoped appropriately to avoid over-rendering consumers
• Consider splitting contexts if different concerns update at different frequencies

[forestileao]

Not sure if that is the correct strategy as discussed with @shiroyasha and @lucaspin