feat(FN-3507): block dispatch when project lacks node mapping

Adds validation to block task dispatch when no project-node mapping exists (FN-3507), including a read helper in CentralCore and a new `node-dispatch-validation` module integrated into the scheduler and in-process runtime, with test coverage across routing and validation scenarios.

Fusion-Task-Id: FN-3507

packages/core/src/__tests__/central-core.test.ts

@@ -804,6 +804,29 @@ describe("CentralCore", () => {
       await expect(central.getProjectNodePathMapping(project.id, nodeA.id)).resolves.toBeUndefined();
     });
 
+    it("should return exact mapped path via getProjectNodePath and undefined for unmapped pairs", async () => {
+      const projectPath = join(tempDir, "mapping-read-project");
+      mkdirSync(projectPath);
+      projectPaths.push(projectPath);
+
+      const project = await central.registerProject({
+        name: "Mapping Read Project",
+        path: projectPath,
+      });
+      const mappedNode = await central.registerNode({ name: "mapping-read-node", type: "local" });
+      const otherNode = await central.registerNode({ name: "mapping-read-node-other", type: "local" });
+
+      await central.upsertProjectNodePathMapping({
+        projectId: project.id,
+        nodeId: mappedNode.id,
+        path: "/mapped/node/path",
+      });
+
+      await expect(central.getProjectNodePath(project.id, mappedNode.id)).resolves.toBe("/mapped/node/path");
+      await expect(central.getProjectNodePath(project.id, otherNode.id)).resolves.toBeUndefined();
+      await expect(central.getProjectNodePath("proj_missing", mappedNode.id)).resolves.toBeUndefined();
+    });
+
     it("should validate project and node existence for mapping APIs", async () => {
       const node = await central.registerNode({ name: "mapping-validation-node", type: "local" });
 

packages/core/src/central-core.ts

@@ -1769,6 +1769,16 @@ export class CentralCore extends EventEmitter<CentralCoreEvents> {
     return row ? this.rowToProjectNodePathMapping(row) : undefined;
   }
 
+  async getProjectNodePath(projectId: string, nodeId: string): Promise<string | undefined> {
+    this.ensureInitialized();
+
+    const row = this.db!
+      .prepare("SELECT path FROM projectNodePathMappings WHERE projectId = ? AND nodeId = ?")
+      .get(projectId, nodeId) as { path: string } | undefined;
+
+    return row?.path;
+  }
+
   async listProjectNodePathMappings(filters?: {
     projectId?: string;
     nodeId?: string;