feat(editor): inner toolbar layout for block (#11243)

Close [BS-2808](https://linear.app/affine-design/issue/BS-2808/组件内-toolbar-重构)

blocksuite/affine/shared/src/services/toolbar-service/config.ts

@@ -3,10 +3,14 @@ import type { Placement } from '@floating-ui/dom';
 import type { ToolbarActions } from './action';
 import type { ToolbarContext } from './context';
 
+export type ToolbarPlacement =
+  | Extract<Placement, 'top' | 'top-start'>
+  | 'inner';
+
 export type ToolbarModuleConfig = {
   actions: ToolbarActions;
 
   when?: ((ctx: ToolbarContext) => boolean) | boolean;
 
-  placement?: Extract<Placement, 'top' | 'top-start'>;
+  placement?: ToolbarPlacement;
 };

blocksuite/affine/shared/src/services/toolbar-service/context.ts

@@ -123,6 +123,10 @@ abstract class ToolbarContextBase {
     return this.toolbarRegistry.flavour$;
   }
 
+  get placement$() {
+    return this.toolbarRegistry.placement$;
+  }
+
   get message$() {
     return this.toolbarRegistry.message$;
   }

blocksuite/affine/shared/src/services/toolbar-service/registry.ts

@@ -4,6 +4,7 @@ import { type Container, createIdentifier } from '@blocksuite/global/di';
 import { Extension, type ExtensionType } from '@blocksuite/store';
 import { signal } from '@preact/signals-core';
 
+import type { ToolbarPlacement } from './config';
 import { Flags } from './flags';
 import type { ToolbarModule } from './module';
 
@@ -33,6 +34,8 @@ export class ToolbarRegistryExtension extends Extension {
     setFloating: (element?: Element) => void;
   } | null>(null);
 
+  placement$ = signal<ToolbarPlacement>('top');
+
   flags = new Flags();
 
   constructor(readonly std: BlockStdScope) {
@@ -43,6 +46,14 @@ export class ToolbarRegistryExtension extends Extension {
     return this.std.provider.getAll(ToolbarModuleIdentifier);
   }
 
+  getModulePlacement(flavour: string, fallback: ToolbarPlacement = 'top') {
+    return (
+      this.modules.get(`custom:${flavour}`)?.config.placement ??
+      this.modules.get(flavour)?.config.placement ??
+      fallback
+    );
+  }
+
   static override setup(di: Container) {
     di.addImpl(ToolbarRegistryIdentifier, this, [StdIdentifier]);
   }