feat(FN-3195): document llama.cpp provider setup and onboarding

Docs(FN-3195): adds llama.cpp provider setup and onboarding documentation to the main and dashboard READMEs.

Fusion-Task-Id: FN-3195

packages/core/src/__tests__/use-llama-cpp-settings.test.ts

@@ -0,0 +1,28 @@
+import { describe, expect, it } from "vitest";
+import type { GlobalSettings } from "../types.js";
+import {
+  DEFAULT_GLOBAL_SETTINGS,
+  GLOBAL_SETTINGS_KEYS,
+  isGlobalSettingsKey,
+} from "../settings-schema.js";
+
+describe("useLlamaCpp global setting", () => {
+  it("is included in GLOBAL_SETTINGS_KEYS", () => {
+    expect(GLOBAL_SETTINGS_KEYS).toContain("useLlamaCpp");
+  });
+
+  it("defaults to undefined", () => {
+    expect(DEFAULT_GLOBAL_SETTINGS.useLlamaCpp).toBeUndefined();
+  });
+
+  it("is recognized by isGlobalSettingsKey", () => {
+    expect(isGlobalSettingsKey("useLlamaCpp")).toBe(true);
+  });
+
+  it("accepts boolean values in GlobalSettings", () => {
+    const enabled: GlobalSettings = { useLlamaCpp: true };
+    const disabled: GlobalSettings = { useLlamaCpp: false };
+    expect(enabled.useLlamaCpp).toBe(true);
+    expect(disabled.useLlamaCpp).toBe(false);
+  });
+});

packages/core/src/settings-schema.ts

@@ -53,6 +53,7 @@ export const DEFAULT_GLOBAL_SETTINGS = {
   modelOnboardingComplete: undefined,
   useClaudeCli: undefined,
   useDroidCli: undefined,
+  useLlamaCpp: undefined,
   // Global baseline lanes for per-role model selection
   executionGlobalProvider: undefined,
   executionGlobalModelId: undefined,

packages/core/src/types.ts

@@ -1403,6 +1403,13 @@ export interface GlobalSettings {
    *  by the dashboard auth toggle. Setting this field explicitly (true/false)
    *  always wins. */
   useDroidCli?: boolean;
+  /** When true, enable llama.cpp model-provider support (provider ID: `llama-server`)
+   *  via Fusion's bundled `@fusion/pi-llama-cpp` extension.
+   *
+   *  When left undefined, llama.cpp routing stays disabled unless explicitly enabled
+   *  by the dashboard auth toggle. Setting this field explicitly (true/false)
+   *  always wins. */
+  useLlamaCpp?: boolean;
   /** Global baseline AI model provider for task execution (executor agent).
    *  This is the global lane that project-level `executionProvider` can override.
    *  Must be set together with `executionGlobalModelId`. Falls back to