Summary

When SynthOrg starts with no configured providers (fresh install), guide the user through initial setup via the web dashboard. Replaces the "edit YAML and restart" workflow entirely.

Flow

1. User runs `synthorg start` → backend + web start

2. User opens dashboard → detects no providers configured

3. Setup page appears (replaces normal dashboard):
   a. Welcome — brief intro, what SynthOrg does
   b. Add provider — preset selector (Ollama, OpenRouter, etc.) or custom. Test connection inline.
   c. Create company — pick a template or start blank. Name, description.
   d. Add first agent — role, model (from just-configured provider), basic budget
   e. Done — redirect to dashboard with the company running

4. After first-run, the setup page is not shown again (a `setup_complete` flag in DB settings)

Existing State

The web dashboard already has a `SetupPage.vue` — currently handles initial admin user creation (JWT setup). This issue extends it to cover provider + company setup.

Dependencies

• feat: implement settings persistence layer (DB-backed config) #450 — Settings persistence layer
• feat: implement provider management (multi-auth, runtime CRUD, local providers) #451 — Provider management (provider CRUD + presets + test endpoint)
• feat: implement company builder interactive wizard (UI + API) #238 — Company builder wizard (the company creation step reuses this)
• feat: implement company builder interactive wizard (UI + API) #238 — Company builder wizard (the company creation step reuses this)

Acceptance Criteria

• Fresh install → setup page shown automatically
• Provider setup with presets and connection test
• Company creation (template or blank)
• First agent creation with model from configured provider
• Setup complete flag persisted — not shown again
• Can be re-triggered via `synthorg setup` CLI or settings reset