docs(style): enforce clickable links for Markdown references

- Add COMMON/docs-style.md with linking rule
- Convert plain Markdown file references to relative links across docs

CTO/AGENTS.md

@@ -1,6 +1,6 @@
 CTO Agent Pack
 
-Use the generated pack for agents: `dist/prompts/cto.md`.
+Use the generated pack for agents: [dist/prompts/cto.md](../../dist/prompts/cto.md).
 
 Includes (via COMMON base):
 - System persona, style, safety
@@ -10,4 +10,3 @@ Includes (via COMMON base):
 
 Notes
 - Keep CTO‑specific additions minimal; prefer COMMON as source of truth.
-