refactor: modularize server.rs into separate route modules

- Extract scan.rs, files.rs, types.rs, processing.rs, visual_chunk_search.rs
- Move AppState and AppConfig to types.rs
- Each module exposes pub fn xxx_routes() -> Router<AppState>
- server.rs reduced from 5005 to 118 lines (orchestrator only)
- All stubs filled with real implementations from git history
- Verify: cargo check, clippy, tests all pass

src/api/identity_binding.rs

@@ -381,7 +381,7 @@ pub struct IdentityTracesResponse {
 }
 
 pub async fn get_identity_traces(
-    State(state): State<crate::api::server::AppState>,
+    State(state): State<crate::api::types::AppState>,
     Path(identity_uuid): Path<String>,
 ) -> Result<Json<IdentityTracesResponse>, (StatusCode, String)> {
     let id_table = crate::core::db::schema::table_name("identities");
@@ -458,7 +458,7 @@ pub async fn get_identity_traces(
     }))
 }
 
-pub fn identity_binding_routes() -> Router<crate::api::server::AppState> {
+pub fn identity_binding_routes() -> Router<crate::api::types::AppState> {
     Router::new()
         .route("/api/v1/identity/:identity_uuid/bind", post(bind_identity))
         .route(