feat(FN-4624): complete Step 0 — preflight worktrunk settings surface

Fusion-Task-Id: FN-4624
Fusion-Task-Lineage: 854e6033-bc17-45be-8d04-18bcb66b31c4

packages/core/src/settings-schema.ts

@@ -165,6 +165,7 @@ export const DEFAULT_GLOBAL_SETTINGS = {
   worktrunk: {
     enabled: false,
     binaryPath: undefined,
+    installedBinaryPath: undefined,
     onFailure: "fail",
   },
   experimentalFeatures: {},
@@ -203,6 +204,7 @@ export const DEFAULT_PROJECT_SETTINGS = {
   worktrunk: {
     enabled: false,
     binaryPath: undefined,
+    installedBinaryPath: undefined,
     onFailure: "fail",
   },
   worktreesDir: undefined,

packages/core/src/types.ts

@@ -1944,6 +1944,9 @@ export interface WorktrunkSettings {
    *  - "fallback-native": fall back to Fusion's built-in worktree-pool and
    *    emit a one-shot dashboard alert. */
   onFailure?: WorktrunkOnFailure;
+  /** Cached install path discovered by the auto-install flow.
+   *  Set by Fusion engine; not intended for manual edits. */
+  installedBinaryPath?: string;
 }
 
 export interface GlobalSettings {
@@ -4749,7 +4752,7 @@ export const AGENT_PERMISSION_POLICY_CATEGORY_TOOL_EXAMPLES: Record<
   git_write: ["git commit", "git push", "git merge", "git branch -d", "git worktree add", "write", "edit"],
   file_write_delete: ["write", "edit", "fn_task_attach"],
   command_execution: ["bash (non-git)", "read", "find", "grep", "ls"],
-  network_api: ["fn_research_run (web/research)", "fn_web_fetch"],
+  network_api: ["fn_research_run (web/research)", "fn_web_fetch", "worktrunk_install"],
   task_agent_mutation: [
     "fn_task_create",
     "fn_delegate_task",

packages/core/src/worktrunk-settings.ts

@@ -6,9 +6,10 @@ const WORKTRUNK_ON_FAILURE_VALUES: readonly WorktrunkOnFailure[] = [
 ] as const;
 
 export const DEFAULT_WORKTRUNK_SETTINGS: Required<Pick<WorktrunkSettings, "enabled" | "onFailure">> &
-  Pick<WorktrunkSettings, "binaryPath"> = {
+  Pick<WorktrunkSettings, "binaryPath" | "installedBinaryPath"> = {
   enabled: false,
   binaryPath: undefined,
+  installedBinaryPath: undefined,
   onFailure: "fail",
 };
 
@@ -22,12 +23,17 @@ export function resolveWorktrunkSettings(
   const enabled = projectValue?.enabled ?? globalValue?.enabled ?? DEFAULT_WORKTRUNK_SETTINGS.enabled;
   const binaryPath =
     projectValue?.binaryPath ?? globalValue?.binaryPath ?? DEFAULT_WORKTRUNK_SETTINGS.binaryPath;
+  const installedBinaryPath =
+    projectValue?.installedBinaryPath ??
+    globalValue?.installedBinaryPath ??
+    DEFAULT_WORKTRUNK_SETTINGS.installedBinaryPath;
   const onFailure =
     projectValue?.onFailure ?? globalValue?.onFailure ?? DEFAULT_WORKTRUNK_SETTINGS.onFailure;
 
   return {
     enabled,
     ...(binaryPath !== undefined ? { binaryPath } : {}),
+    ...(installedBinaryPath !== undefined ? { installedBinaryPath } : {}),
     onFailure,
   };
 }
@@ -70,5 +76,16 @@ export function validateWorktrunkSettings(value: unknown): WorktrunkSettings {
     validated.onFailure = input.onFailure as WorktrunkOnFailure;
   }
 
+  if (input.installedBinaryPath !== undefined) {
+    if (typeof input.installedBinaryPath !== "string") {
+      throw new Error("worktrunk.installedBinaryPath must be a string when set");
+    }
+    const trimmed = input.installedBinaryPath.trim();
+    if (trimmed.length === 0) {
+      throw new Error("worktrunk.installedBinaryPath cannot be empty");
+    }
+    validated.installedBinaryPath = trimmed;
+  }
+
   return validated;
 }