Add screenshots and private preview warning to getting-started docs

- Add runs board screenshot to introduction page
- Add run detail and workflow diagram screenshots to why-arc page
- Add private research preview warning to quick-start page

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/getting-started/introduction.mdx

@@ -5,6 +5,8 @@ description: "Arc is the software factory for small teams of expert engineers"
 
 Arc replaces the prompt-wait-review loop with version-controlled workflow graphs that orchestrate AI agents, shell commands, and human decisions into repeatable, long-horizon coding processes.
 
+<img src="/images/runs-board.png" alt="Arc Runs board showing workflows across Working, Pending, Verify, and Merge stages" />
+
 <Columns cols={2}>
   <Card
     title="Why Arc?"

docs/getting-started/quick-start.mdx

@@ -3,6 +3,10 @@ title: "Quick Start"
 description: "Get up and running with Arc"
 ---
 
+<Warning>
+  Arc is in private research preview. Contact [bryan@qlty.sh](mailto:bryan@qlty.sh) if you're interested in trying it.
+</Warning>
+
 ## Prerequisites
 
 - [Rust](https://rustup.rs/) (latest stable)

docs/getting-started/why-arc.mdx

@@ -15,6 +15,8 @@ AI coding agents have transformed software engineering productivity, but the sur
 - **Token costs are primed to explode.** ROI per token diverges wildly across tasks, models, and harnesses. Every unnecessary frontier token is one that can't be spent where it matters.
 - **The continuous improvement loop broke.** Data is lost at every sub-process boundary. Organizations can't train LLMs the way they train people, and memory files make no guarantees.
 
+<img src="/images/run-detail.png" alt="Arc run detail view showing verifications for a pipeline event types change, including Traceability, Readability, Reliability, Code Coverage, and more" />
+
 ## How Arc solves this
 
 Arc gives you a deterministic harness around non-deterministic AI. You define **workflow graphs** in DOT files that specify exactly what happens, in what order, with which models, and where humans weigh in. Arc handles orchestration, parallelism, model routing, verification, and observability.
@@ -40,6 +42,8 @@ Arc gives you a deterministic harness around non-deterministic AI. You define **
   </Card>
 </Columns>
 
+<img src="/images/workflow-example.png" alt="Arc workflow diagram for Fix Build showing stages from Start through Analyze Build Errors, Diagnose Root Cause, Validate Build, and Review Changes to Exit" />
+
 ## What a workflow looks like
 
 Workflows are defined in Graphviz DOT, a simple graph description language. Here's a plan-approve-implement workflow and its DOT source: