Config: Change server port to 6800 and remove Cargo.lock dependency

Changes:
- Changed server port from 8000 to 6800 (in range 6500-6999 as requested)
- Updated all Docker Compose files (dev and prod)
- Updated all Dockerfiles (removed Cargo.lock dependency)
- Created backend/.dockerignore with Cargo.lock
- Added Cargo.lock to .gitignore (generated by cargo)
- Removed obsolete 'version' attribute from docker-compose files
- Updated all documentation to reflect new port:
  * README.md
  * thoughts/CONFIG.md
  * thoughts/QUICKSTART.md
  * thoughts/verification-report-phase-2.3.md

This fixes Docker build errors where Cargo.lock was not found during COPY operations.
Docker will now generate Cargo.lock during the build process as expected.

.gitignore

@@ -22,3 +22,78 @@ Thumbs.db
 
 # Logs
 *.log
+
+# Rust
+backend/target/
+backend/Cargo.lock
+
+# Node.js
+mobile/node_modules/
+web/node_modules/
+shared/node_modules/
+
+# Environment files
+backend/.env
+mobile/.env
+web/.env
+
+# IDE
+.vscode/
+.idea/
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Logs
+*.log
+
+# Rust
+backend/target/
+backend/Cargo.lock
+
+# Node.js
+mobile/node_modules/
+web/node_modules/
+shared/node_modules/
+
+# Environment files
+backend/.env
+mobile/.env
+web/.env
+
+# IDE
+.vscode/
+.idea/
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Logs
+*.log
+
+# Rust
+backend/target/
+backend/Cargo.lock
+
+# Node.js
+mobile/node_modules/
+web/node_modules/
+shared/node_modules/
+
+# Environment files
+backend/.env
+mobile/.env
+web/.env
+
+# IDE
+.vscode/
+.idea/
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Logs
+*.log