docs(FN-1158): add comprehensive project documentation suite

- Add docs index with structured navigation and links across the new documentation set
- Document onboarding and technical foundations with getting-started and architecture guides
- Add detailed CLI and settings references plus feature guides for dashboard, tasks, workflow steps, missions, multi-project, and agents
- Add a contributing guide and polish cross-references between docs pages for discoverability
- Include dashboard screenshots for key views to provide visual context in the guides

docs/getting-started.md

@@ -0,0 +1,133 @@
+# Getting Started
+
+[← Docs index](./README.md)
+
+This guide gets Fusion running, explains first-run setup, and walks through your first task from creation to completion.
+
+## Prerequisites
+
+Fusion uses the `pi` agent runtime for AI sessions.
+
+1. Install pi:
+
+```bash
+npm i -g @mariozechner/pi-coding-agent
+```
+
+2. Authenticate pi (for example with `/login`) or configure provider API keys.
+
+```bash
+pi
+```
+
+## Install Fusion
+
+Install the published CLI package globally:
+
+```bash
+npm i -g @gsxdsm/fusion
+```
+
+Then verify install:
+
+```bash
+fn --help
+```
+
+## First Run and Onboarding
+
+Start the dashboard:
+
+```bash
+fn dashboard
+```
+
+On first launch, Fusion opens the **model onboarding wizard**. It guides you through:
+
+- Choosing one or more AI providers
+- Authenticating providers (OAuth or API key)
+- Selecting a default model
+
+Onboarding completion is tracked by `modelOnboardingComplete` in global settings.
+
+## Start the Dashboard
+
+Common startup options:
+
+```bash
+fn dashboard                       # default port 4040
+fn dashboard --port 5050          # custom port
+fn dashboard --interactive        # choose port interactively
+fn dashboard --paused             # start with automation paused
+fn dashboard --dev                # run UI only (no engine)
+```
+
+Open: `http://localhost:4040`
+
+## Create Your First Task
+
+You can create tasks from the board or CLI.
+
+### Option A: Quick Entry (Board)
+
+1. Type a short request in the quick entry input.
+2. Press Enter.
+3. Task appears in **Triage** and the triage agent generates `PROMPT.md`.
+
+### Option B: Plan Mode (Board)
+
+Use the 💡 button to open AI planning mode:
+
+- Fusion asks clarifying questions
+- Produces a structured summary
+- Lets you create one task or break into multiple dependency-linked tasks
+
+### Option C: Subtask Breakdown (Board)
+
+Use the 🌳 button to:
+
+- Generate 2–5 subtasks
+- Reorder by drag-and-drop
+- Add dependency links before creating tasks
+
+### Option D: CLI
+
+```bash
+fn task create "Fix flaky login test"
+fn task plan "Implement role-based access control"
+```
+
+## Understand the Task Lifecycle
+
+Fusion uses six columns:
+
+1. **Triage** — raw idea; AI writes spec
+2. **Todo** — specified and queued
+3. **In Progress** — executor implements in a dedicated worktree
+4. **In Review** — implementation complete, awaiting merge/finalization
+5. **Done** — merged and complete
+6. **Archived** — retained for history, optionally cleaned up from filesystem
+
+## Daily CLI Commands
+
+```bash
+fn task list
+fn task show FN-001
+fn task logs FN-001 --follow --limit 50
+fn task steer FN-001 "Prefer existing utility functions"
+fn task pause FN-001
+fn task unpause FN-001
+```
+
+## Dashboard Orientation (Annotated)
+
+![Dashboard board view with key UI areas](./screenshots/dashboard-overview.png)
+
+Suggested way to read the screen:
+
+- **Top bar:** global actions (settings, activity, mission/agent tools)
+- **Columns:** task lifecycle stages
+- **Task cards:** status, metadata, PR/issue badges
+- **Quick entry:** fastest way to create a new task
+
+Next: [Architecture](./architecture.md) for internals, or [Task Management](./task-management.md) for deeper task workflows.