Refactor: Convert repository structure from technical layers to Domain-Driven Design (DDD)

## Context

This issue is a follow-up to PR #8860 which added the CurveEditor component. During review, it was identified that the repository would benefit from migrating from a technical layer structure to Domain-Driven Design (DDD).

## Current State

The repository currently uses technical layers with top-level directories like:
- `src/composables`
- `src/components`

## Desired State

Reorganize the codebase to follow Domain-Driven Design principles by grouping related functionality by domain rather than by technical type.

## Proposed Structure

- **Renderer domain**: All rendering-related components, composables, and logic should be moved to the `renderer` domain
- **Base folder**: Pure, reusable utility functions that are domain-agnostic
- **Graph domain**: Graph-related code should be in `core/graph`
- **Workspace domain**: Workspace and chrome UI components should be in `src/workspace`

## Migration Tasks

- [ ] Audit all files in `src/composables` and move to appropriate domains
- [ ] Audit all files in `src/components` and move to appropriate domains
- [ ] Update import paths throughout the codebase
- [ ] Update any build configurations or path aliases as needed
- [ ] Update documentation to reflect the new structure

## References

- Requested by: @christian-byrne
- Related PR: #8860
- Related comment: https://github.com/Comfy-Org/ComfyUI_frontend/pull/8860#discussion_r2838844911

## Note

This is a significant refactoring effort that should be planned carefully to minimize disruption. Consider breaking this into smaller, incremental PRs by domain.

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-9108-Refactor-Convert-repository-structure-from-technical-layers-to-Domain-Driven-Design--3106d73d365081e5b3fdcfba14b9a5fa) by [Unito](https://www.unito.io)

Start by auditing the files under src/composables and src/components, then review PR #8860 and its related discussion for the motivation. Plan the migration by domain: renderer, base, core/graph, and src/workspace. Done means imports and build or path-alias configuration work with the reorganized structure and the documentation reflects it.

Written by the indexing model from the issue text.