chore: macOS to Linux migration complete

All platform-specific paths and commands replaced with Linux equivalents:
- .git_path: Use system git instead of /Library/Developer/CommandLineTools
- start_server.sh: Use hostname -I instead of ipconfig
- AI_RULES.md line 18: Remove macOS path mandate
- PROJECT_ARCHITECTURE.md Section 7.5: Document Linux native approach
- SESSION_STATE.md: Update git binary reference

Ready for Ubuntu development, Docker testing, and standalone deployment.

.claude/settings.local.json

@@ -41,7 +41,8 @@
       "Bash(command -v npx)",
       "Bash(cat)",
       "Read(//tmp/**)",
-      "Bash(save-version --help)"
+      "Bash(save-version --help)",
+      "Bash(git --version)"
     ]
   }
 }