Standardize workspace: Capitalize Justfile references in scripts and docs

Author: hyperpolymath

CONTRIBUTING.md

@@ -43,7 +43,7 @@ live-files/
 ├── README.adoc
 ├── SECURITY.md
 ├── flake.nix            # Nix flake (Perimeter 1)
-└── justfile             # Task runner (Perimeter 1)
+└── Justfile             # Task runner (Perimeter 1)
 ```
 
 ---

README.adoc

@@ -47,7 +47,7 @@ just file
 ----
 live-files/
 +-- 0-AI-MANIFEST.a2ml         # AI agent entry point
-+-- justfile                    # Task runner (no Makefiles)
++-- Justfile                    # Task runner (no Makefiles)
 +-- must                        # Restoration utility
 +-- scripts/
 |   +-- map_ecosystem.sh        # Colour-coded fleet map