fix: commit Cargo.lock for reproducible builds

Cargo.lock should be committed for applications (not libraries) to ensure
reproducible builds across environments. This is required for Docker builds
and is the recommended practice per Rust guidelines.

Removed Cargo.lock from:
- .gitignore
- .dockerignore

This fixes the Docker build error:
  ERROR: "/Cargo.lock": not found

.dockerignore

@@ -12,7 +12,7 @@
 
 # Rust
 target/
-Cargo.lock
+# Note: Cargo.lock is needed for reproducible builds
 
 # Build artifacts
 *.db

.gitignore

@@ -4,7 +4,7 @@
 *.pdb
 
 # Cargo
-Cargo.lock
+# Note: Cargo.lock should be committed for applications (not ignored)
 
 # IDE and editor files
 .idea/