FN-5805: add fn onboard command with sequential runOnboard flow

Add a new interactive onboarding CLI flow that guides first-time setup end to end.

- add new `fn onboard` command wiring in CLI entrypoint and usage help
- implement `runOnboard()` with sequential prompts for central DB, provider auth, init, test mode, and project maxConcurrent
- persist `cliOnboardingCompletedAt` marker in global settings with `--force` rerun support
- add onboarding command tests and global settings regression coverage
- document `fn onboard` usage and options in CLI reference
- add a minor changeset for published `@runfusion/fusion`

Files changed:
 .changeset/fn-5805-onboard-command.md              |   5 +
 docs/cli-reference.md                              |  20 ++
 packages/cli/src/bin.ts                            |  10 +
 packages/cli/src/commands/__tests__/onboard.test.ts| 193 ++++++++++++++++
 packages/cli/src/commands/onboard.ts               | 249 +++++++++++++++++++++
 packages/core/src/__tests__/global-settings.test.ts|  11 +
 packages/core/src/index.ts                         |   2 +-
 packages/core/src/settings-schema.ts               |   1 +
 packages/core/src/types.ts                         |   4 +
 9 files changed, 494 insertions(+), 1 deletion(-)

Fusion-Task-Id: FN-5805

Fusion-Task-Lineage: b1bcaf27-9bd7-4569-b685-225a97fa1200

packages/cli/src/bin.ts

@@ -131,6 +131,7 @@ async function loadCommandHandlers() {
   const { runProjectList, runProjectAdd, runProjectRemove, runProjectShow, runProjectInfo, runProjectSetDefault, runProjectDetect } = await import("./commands/project.js");
   const { runNodeList, runNodeConnect, runNodeDisconnect, runNodeShow, runNodeHealth, runMeshStatus } = await import("./commands/node.js");
   const { runInit } = await import("./commands/init.js");
+  const { runOnboard } = await import("./commands/onboard.js");
   const { runAgentStop, runAgentStart } = await import("./commands/agent.js");
   const { runAgentImport } = await import("./commands/agent-import.js");
   const { runAgentExport } = await import("./commands/agent-export.js");
@@ -212,6 +213,7 @@ async function loadCommandHandlers() {
     runNodeHealth,
     runMeshStatus,
     runInit,
+    runOnboard,
     runAgentStop,
     runAgentStart,
     runAgentImport,
@@ -253,6 +255,7 @@ fn — AI-orchestrated task board
 Usage:
   fn                                  Launch the dashboard (same as fn dashboard)
   fn init [opts]                      Initialize a new fn project (--name, --path, --git)
+  fn onboard [--force]                Run the interactive onboarding wizard
   fn dashboard                        Start the board web UI
   fn dashboard --paused               Start with automation paused
   fn dashboard --dev                  Start web UI only (no AI engine)
@@ -623,6 +626,7 @@ async function main() {
     runNodeHealth,
     runMeshStatus,
     runInit,
+    runOnboard,
     runAgentStop,
     runAgentStart,
     runAgentImport,
@@ -671,6 +675,12 @@ async function main() {
         break;
       }
 
+      case "onboard": {
+        const force = args.includes("--force");
+        await runOnboard({ force });
+        break;
+      }
+
       case "dashboard": {
         // Initialize native module resolution for Bun binary before starting dashboard
         // This sets up the paths so node-pty can find its native assets