Add graph explorer components, API handlers, and dependency updates

Adds code inspector, file tree components, graph visualization JS,
graph API handlers, sidebar navigation updates, and misc improvements.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

compliance-graph/Cargo.toml

@@ -31,7 +31,7 @@ petgraph = "0.7"
 tantivy = "0.22"
 
 # Serialization
-bson = "2"
+bson = { version = "2", features = ["chrono-0_4"] }
 
 # Async streams
 futures-util = "0.3"