feat: backfill Claude skills when useClaudeCli toggle flips on

PUT /api/settings/global now fires an onUseClaudeCliToggled hook on an
actual transition so the UI toggle has immediate effect — serve/daemon/
dashboard wire it to ensureClaudeSkillsForAllProjectsOnStartup so every
registered project picks up .claude/skills/fusion without a restart.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/cli/src/commands/daemon.ts

@@ -460,6 +460,22 @@ export async function runDaemon(opts: DaemonOptions = {}) {
     onProjectRegistered: ({ path }) => {
       maybeInstallClaudeSkillForNewProject(path);
     },
+    onUseClaudeCliToggled: (_prev, next) => {
+      if (!next) return;
+      void (async () => {
+        try {
+          if (!sharedCentralCore) return;
+          const projects = await sharedCentralCore.listProjects();
+          ensureClaudeSkillsForAllProjectsOnStartup(
+            projects.map((p) => ({ id: p.id, name: p.name, path: p.path })),
+          );
+        } catch (err) {
+          console.warn(
+            `[fusion] Claude skill backfill on toggle failed: ${err instanceof Error ? err.message : String(err)}`,
+          );
+        }
+      })();
+    },
     headless: true,
     daemon: { token: daemonToken },
     skillsAdapter,

packages/cli/src/commands/dashboard.ts

@@ -1000,6 +1000,23 @@ export async function runDashboard(port: number, opts: { paused?: boolean; dev?:
       onProjectRegistered: ({ path }) => {
         maybeInstallClaudeSkillForNewProject(path);
       },
+      onUseClaudeCliToggled: (_prev, next) => {
+        if (!next) return;
+        void (async () => {
+          try {
+            if (!centralCoreForEngine) return;
+            const projects = await centralCoreForEngine.listProjects();
+            ensureClaudeSkillsForAllProjectsOnStartup(
+              projects.map((p) => ({ id: p.id, name: p.name, path: p.path })),
+            );
+          } catch (err) {
+            logSink.log(
+              `Claude skill backfill on toggle failed: ${err instanceof Error ? err.message : String(err)}`,
+              "engine",
+            );
+          }
+        })();
+      },
       skillsAdapter,
       https: loadTlsCredentialsFromEnv(),
       daemon: dashboardAuthToken ? { token: dashboardAuthToken } : undefined,
@@ -1191,6 +1208,23 @@ export async function runDashboard(port: number, opts: { paused?: boolean; dev?:
       onProjectRegistered: ({ path }) => {
         maybeInstallClaudeSkillForNewProject(path);
       },
+      onUseClaudeCliToggled: (_prev, next) => {
+        if (!next) return;
+        void (async () => {
+          try {
+            if (!centralCoreForMesh) return;
+            const projects = await centralCoreForMesh.listProjects();
+            ensureClaudeSkillsForAllProjectsOnStartup(
+              projects.map((p) => ({ id: p.id, name: p.name, path: p.path })),
+            );
+          } catch (err) {
+            logSink.log(
+              `Claude skill backfill on toggle failed: ${err instanceof Error ? err.message : String(err)}`,
+              "engine",
+            );
+          }
+        })();
+      },
       skillsAdapter,
       https: loadTlsCredentialsFromEnv(),
       daemon: dashboardAuthToken ? { token: dashboardAuthToken } : undefined,

packages/cli/src/commands/serve.ts

@@ -621,6 +621,22 @@ export async function runServe(
       // is configured. The runner logs its own outcome and swallows errors.
       maybeInstallClaudeSkillForNewProject(path);
     },
+    onUseClaudeCliToggled: (_prev, next) => {
+      if (!next) return; // Toggle-off leaves existing skill symlinks alone.
+      void (async () => {
+        try {
+          if (!sharedCentralCore) return;
+          const projects = await sharedCentralCore.listProjects();
+          ensureClaudeSkillsForAllProjectsOnStartup(
+            projects.map((p) => ({ id: p.id, name: p.name, path: p.path })),
+          );
+        } catch (err) {
+          console.warn(
+            `[fusion] Claude skill backfill on toggle failed: ${err instanceof Error ? err.message : String(err)}`,
+          );
+        }
+      })();
+    },
     headless: true,
     skillsAdapter,
     daemon: daemonToken ? { token: daemonToken } : undefined,