feat(FN-3803): add universal web fetch to reviewer, merger, and triage agen

The merge introduces the universal web fetch tool across reviewer/merger/triage agents (FN-3803, 4 commits) with docs and regression test, extracts the roadmap as a plugin scaffold in `plugins/fusion-plugin-reports` (FN-3166, FN-3165) while removing dashboard roadmap backend and associated tests, ad

Fusion-Task-Id: FN-3803

packages/engine/src/__tests__/reviewer.test.ts

@@ -201,7 +201,7 @@ describe("reviewStep — spec review type", () => {
     const opts = mockedCreateFnAgent.mock.calls[0][0];
     expect(opts.systemPrompt).toContain("## Project Memory");
     expect(opts.systemPrompt).toContain("Do not update memory during review");
-    expect(opts.customTools?.map((tool: any) => tool.name)).toEqual(["fn_memory_search", "fn_memory_get"]);
+    expect(opts.customTools?.map((tool: any) => tool.name)).toEqual(["fn_web_fetch", "fn_memory_search", "fn_memory_get"]);
   });
 
   it("omits reviewer memory tools and instructions when memory is disabled", async () => {
@@ -217,7 +217,7 @@ describe("reviewStep — spec review type", () => {
 
     const opts = mockedCreateFnAgent.mock.calls[0][0];
     expect(opts.systemPrompt).not.toContain("## Project Memory");
-    expect(opts.customTools).toBeUndefined();
+    expect(opts.customTools?.map((tool: any) => tool.name)).toEqual(["fn_web_fetch"]);
   });
 
   it("builds review request with spec-specific instructions", async () => {

packages/engine/src/__tests__/web-fetch-universal.test.ts

@@ -0,0 +1,36 @@
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
+import { describe, expect, it } from "vitest";
+
+function readSource(file: string): string {
+  return readFileSync(join(import.meta.dirname, "..", file), "utf8");
+}
+
+describe("fn_web_fetch universal registration", () => {
+  it("executor registers fn_web_fetch", () => {
+    expect(readSource("executor.ts")).toContain("createWebFetchTool()");
+  });
+
+  it("step-session executor registers fn_web_fetch", () => {
+    expect(readSource("step-session-executor.ts")).toContain("createWebFetchTool()");
+  });
+
+  it("reviewer registers fn_web_fetch", () => {
+    expect(readSource("reviewer.ts")).toContain("customTools: [createWebFetchTool()");
+  });
+
+  it("merger registers fn_web_fetch", () => {
+    expect(readSource("merger.ts")).toContain("customTools: [reportBuildFailureTool, createWebFetchTool()]");
+  });
+
+  it("triage registers fn_web_fetch", () => {
+    expect(readSource("triage.ts")).toContain("createWebFetchTool(),");
+  });
+
+  it("heartbeat registers fn_web_fetch for task and no-task branches", () => {
+    const source = readSource("agent-heartbeat.ts");
+    expect(source).toContain("heartbeatTools.push(createWebFetchTool())");
+    expect(source).toContain("if (taskId)");
+    expect(source).toContain("else {");
+  });
+});