docs: add quickstart guide

Author: OgeonX-Ai

docs/methodology/quickstart.md

@@ -0,0 +1,34 @@
+# Quickstart
+
+Use this page to apply AI-OS to any repository.
+
+## Quickstart loop
+
+```mermaid
+flowchart TD
+    A[Choose task] --> B[Read AGENTS.md]
+    B --> C[Load project context]
+    C --> D[Select loop]
+    D --> E[Plan]
+    E --> F[Work in increments]
+    F --> G[Verify]
+    G --> H{Done?}
+    H -- No --> F
+    H -- Yes --> I[Report]
+```
+
+## Minimal prompt
+
+```text
+Execute AI-OS.
+Task: [describe task]
+Load context, choose the loop, plan, work, verify, and report evidence.
+```
+
+## First repository setup
+
+1. Add `AGENTS.md`.
+2. Add project context.
+3. Add verifier commands.
+4. Add loop-specific prompts.
+5. Add CI checks.