feat: Organize context files and enhance documentation for clarity and structure

ai/context/systems/index.md

@@ -0,0 +1,23 @@
+# Systems Index
+
+## Core Components
+
+- [fid4.md](./fid4.md)
+  Consumer app and the most important real-world validation environment.
+
+- [xflowsdk.md](./xflowsdk.md)
+  Backend-driven flow engine and the center of most Fidelity behavior analysis.
+
+- [xflowviewmaker.md](./xflowviewmaker.md)
+  Adapter layer historically involved in version bumps, release coupling, and removal evaluation.
+
+- [ftframeworks.md](./ftframeworks.md)
+  Consumer-side feature modules that often mediate whether XFlow changes can be validated in Fid4.
+
+---
+
+## Guidance
+
+- Start with `xflowsdk.md` for backend-driven behavior questions.
+- Start with `fid4.md` or `ftframeworks.md` for consumer validation and release flow questions.
+- Open `xflowviewmaker.md` when the question involves version bumps, transitional architecture, or pipeline friction.