refactor: migrate keybindings to DDD structure (#8369)

## Summary

Migrate keybindings domain to `src/platform/keybindings/` following DDD
principles.

## Changes

- **What**: Consolidate keybinding-related code (types, store, service,
defaults, reserved keys) into a single domain module with flat structure
- Extracted `KeyComboImpl` and `KeybindingImpl` classes into separate
files
- Updated all consumers to import from new location
- Colocated tests with source files
- Updated stores/README.md and services/README.md to remove migrated
entries

## Review Focus

- Verify all import paths were updated correctly
- Check that the flat structure is appropriate (vs nested core/data/ui
layers)

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8369-refactor-migrate-keybindings-to-DDD-structure-2f66d73d36508120b169dc737075fb45)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Subagent 5 <subagent@example.com>
Co-authored-by: Amp <amp@ampcode.com>

src/platform/keybindings/defaults.ts

@@ -0,0 +1,198 @@
+import type { Keybinding } from './types'
+
+export const CORE_KEYBINDINGS: Keybinding[] = [
+  {
+    combo: {
+      ctrl: true,
+      key: 'Enter'
+    },
+    commandId: 'Comfy.QueuePrompt'
+  },
+  {
+    combo: {
+      ctrl: true,
+      shift: true,
+      key: 'Enter'
+    },
+    commandId: 'Comfy.QueuePromptFront'
+  },
+  {
+    combo: {
+      ctrl: true,
+      alt: true,
+      key: 'Enter'
+    },
+    commandId: 'Comfy.Interrupt'
+  },
+  {
+    combo: {
+      key: 'r'
+    },
+    commandId: 'Comfy.RefreshNodeDefinitions'
+  },
+  {
+    combo: {
+      key: 'w'
+    },
+    commandId: 'Workspace.ToggleSidebarTab.workflows'
+  },
+  {
+    combo: {
+      key: 'n'
+    },
+    commandId: 'Workspace.ToggleSidebarTab.node-library'
+  },
+  {
+    combo: {
+      key: 'm'
+    },
+    commandId: 'Workspace.ToggleSidebarTab.model-library'
+  },
+  {
+    combo: {
+      key: 's',
+      ctrl: true
+    },
+    commandId: 'Comfy.SaveWorkflow'
+  },
+  {
+    combo: {
+      key: 'o',
+      ctrl: true
+    },
+    commandId: 'Comfy.OpenWorkflow'
+  },
+  {
+    combo: {
+      key: 'g',
+      ctrl: true
+    },
+    commandId: 'Comfy.Graph.GroupSelectedNodes'
+  },
+  {
+    combo: {
+      key: ',',
+      ctrl: true
+    },
+    commandId: 'Comfy.ShowSettingsDialog'
+  },
+  {
+    combo: {
+      key: '=',
+      alt: true
+    },
+    commandId: 'Comfy.Canvas.ZoomIn',
+    targetElementId: 'graph-canvas'
+  },
+  {
+    combo: {
+      key: '+',
+      alt: true,
+      shift: true
+    },
+    commandId: 'Comfy.Canvas.ZoomIn',
+    targetElementId: 'graph-canvas'
+  },
+  {
+    combo: {
+      key: '+',
+      alt: true
+    },
+    commandId: 'Comfy.Canvas.ZoomIn',
+    targetElementId: 'graph-canvas'
+  },
+  {
+    combo: {
+      key: '-',
+      alt: true
+    },
+    commandId: 'Comfy.Canvas.ZoomOut',
+    targetElementId: 'graph-canvas'
+  },
+  {
+    combo: {
+      key: '.'
+    },
+    commandId: 'Comfy.Canvas.FitView',
+    targetElementId: 'graph-canvas-container'
+  },
+  {
+    combo: {
+      key: 'p'
+    },
+    commandId: 'Comfy.Canvas.ToggleSelected.Pin',
+    targetElementId: 'graph-canvas-container'
+  },
+  {
+    combo: {
+      key: 'c',
+      alt: true
+    },
+    commandId: 'Comfy.Canvas.ToggleSelectedNodes.Collapse',
+    targetElementId: 'graph-canvas-container'
+  },
+  {
+    combo: {
+      key: 'b',
+      ctrl: true
+    },
+    commandId: 'Comfy.Canvas.ToggleSelectedNodes.Bypass',
+    targetElementId: 'graph-canvas-container'
+  },
+  {
+    combo: {
+      key: 'm',
+      ctrl: true
+    },
+    commandId: 'Comfy.Canvas.ToggleSelectedNodes.Mute',
+    targetElementId: 'graph-canvas-container'
+  },
+  {
+    combo: {
+      key: '`',
+      ctrl: true
+    },
+    commandId: 'Workspace.ToggleBottomPanelTab.logs-terminal'
+  },
+  {
+    combo: {
+      key: 'e',
+      ctrl: true,
+      shift: true
+    },
+    commandId: 'Comfy.Graph.ConvertToSubgraph'
+  },
+  {
+    combo: {
+      key: 'm',
+      alt: true
+    },
+    commandId: 'Comfy.Canvas.ToggleMinimap'
+  },
+  {
+    combo: {
+      ctrl: true,
+      shift: true,
+      key: 'k'
+    },
+    commandId: 'Workspace.ToggleBottomPanel.Shortcuts'
+  },
+  {
+    combo: {
+      key: 'v'
+    },
+    commandId: 'Comfy.Canvas.Unlock'
+  },
+  {
+    combo: {
+      key: 'h'
+    },
+    commandId: 'Comfy.Canvas.Lock'
+  },
+  {
+    combo: {
+      key: 'Escape'
+    },
+    commandId: 'Comfy.Graph.ExitSubgraph'
+  }
+]