feat: add "Anthropic — via Claude CLI" as a first-class provider

Replaces the stray useClaudeCli settings checkbox + onboarding question
with a proper provider-card UX. The card lives next to OAuth + API-key
cards in onboarding and settings, with Enable/Disable + Test actions.

Backend:
 - Vendors rchern/pi-claude-cli@0.3.1 as packages/pi-claude-cli
   (MIT, attribution in UPSTREAM.md). Lets us bump peer-dep on
   pi-coding-agent in lockstep with Fusion (upstream pinned ^0.52.0
   vs ours ^0.62.0) and fix bugs without waiting on upstream.
 - Adds @fusion/pi-claude-cli as a workspace dep of @runfusion/fusion
   so users don't have to `npm install -g pi-claude-cli` manually.
 - serve/daemon/dashboard conditionally load the extension via
   discoverAndLoadExtensions() when GlobalSettings.useClaudeCli is on;
   no side-effects on user ~/.fusion/agent/settings.json.
 - New GET /api/providers/claude-cli/status: claude --version probe
   + toggle state + cached extension resolution.
 - New POST /api/auth/claude-cli: flips useClaudeCli, refuses if the
   claude binary is missing, fires the existing skill-backfill hook.
 - /api/auth/status now injects a synthetic {id:"claude-cli", type:"cli"}
   provider entry so onboarding + settings see a consistent list.

Frontend:
 - New ClaudeCliProviderCard component shared between ModelOnboardingModal
   and SettingsModal's Authentication section.
 - New AuthProvider.type = "cli" variant.
 - Removed the old "Route AI calls through the Claude CLI" checkbox from
   Global Models settings and the opt-in step from the onboarding wizard.
 - ProviderIcon gets a composite Anthropic-mark-plus-terminal glyph for
   the claude-cli provider id.

Tests:
 - 8 unit tests for extension resolution (@fusion/pi-claude-cli is
   workspace-linked so these run in-tree).
 - 2 unit tests for the binary probe.
 - Existing /auth/status tests filter out the new synthetic entry so
   they keep asserting structural OAuth/API-key behavior in isolation.
 - The vendored package's own 296 tests still pass unchanged.

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

packages/cli/src/commands/daemon.ts

@@ -42,6 +42,11 @@ import {
   ensureClaudeSkillsForAllProjectsOnStartup,
   maybeInstallClaudeSkillForNewProject,
 } from "./claude-skills-runner.js";
+import {
+  getCachedClaudeCliResolution,
+  resolveClaudeCliExtensionPaths,
+  setCachedClaudeCliResolution,
+} from "./claude-cli-extension.js";
 import { createReadOnlyAuthFileStorage, mergeAuthStorageReads, wrapAuthStorageWithApiKeyProviders } from "./provider-auth.js";
 import { getFusionAuthPath, getLegacyAuthPaths, getModelRegistryModelsPath, getPackageManagerAgentDir } from "./auth-paths.js";
 import { resolveProject } from "../project-context.js";
@@ -387,8 +392,30 @@ export async function runDaemon(opts: DaemonOptions = {}) {
       .filter((r) => r.enabled)
       .map((r) => r.path);
 
+    const claudeCliPaths = await (async () => {
+      try {
+        const globalSettings = await store.getGlobalSettingsStore().getSettings();
+        const result = resolveClaudeCliExtensionPaths(globalSettings);
+        setCachedClaudeCliResolution(result.resolution);
+        if (result.warning) {
+          console.warn(`[extensions] pi-claude-cli: ${result.warning}`);
+        }
+        return result.paths;
+      } catch (err) {
+        console.warn(
+          `[extensions] Unable to evaluate useClaudeCli setting: ${err instanceof Error ? err.message : String(err)}`,
+        );
+        setCachedClaudeCliResolution(null);
+        return [];
+      }
+    })();
+
     const extensionsResult = await discoverAndLoadExtensions(
-      [...getEnabledPiExtensionPaths(cwd), ...packageExtensionPaths],
+      [
+        ...getEnabledPiExtensionPaths(cwd),
+        ...packageExtensionPaths,
+        ...claudeCliPaths,
+      ],
       cwd,
       join(cwd, ".fusion", "disabled-auto-extension-discovery"),
     );
@@ -460,6 +487,17 @@ export async function runDaemon(opts: DaemonOptions = {}) {
     onProjectRegistered: ({ path }) => {
       maybeInstallClaudeSkillForNewProject(path);
     },
+    getClaudeCliExtensionStatus: () => {
+      const r = getCachedClaudeCliResolution();
+      if (!r) return null;
+      if (r.status === "ok") {
+        return { status: "ok", path: r.path, packageVersion: r.packageVersion };
+      }
+      if (r.status === "not-installed") {
+        return { status: "not-installed" };
+      }
+      return { status: r.status, reason: r.reason };
+    },
     onUseClaudeCliToggled: (_prev, next) => {
       if (!next) return;
       void (async () => {