feat: enhance tracing with field attributes and warn logging across all handlers

Add repo_id, finding_id, and filter fields to tracing::instrument attributes
for better trace correlation in SigNoz. Replace all silently swallowed errors
(Err(_) => Vec::new()) with tracing::warn! logging across mod.rs, dast.rs,
graph.rs handlers. Add stage-level spans with .instrument() to pipeline
orchestrator for visibility into scan phases.

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

compliance-agent/src/api/handlers/graph.rs

@@ -33,7 +33,7 @@ fn default_search_limit() -> usize {
 }
 
 /// GET /api/v1/graph/:repo_id — Full graph data
-#[tracing::instrument(skip_all)]
+#[tracing::instrument(skip_all, fields(repo_id = %repo_id))]
 pub async fn get_graph(
     Extension(agent): AgentExt,
     Path(repo_id): Path<String>,
@@ -55,11 +55,17 @@ pub async fn get_graph(
 
         let all_nodes: Vec<CodeNode> = match db.graph_nodes().find(filter.clone()).await {
             Ok(cursor) => collect_cursor_async(cursor).await,
-            Err(_) => Vec::new(),
+            Err(e) => {
+                tracing::warn!("Failed to fetch graph nodes: {e}");
+                Vec::new()
+            }
         };
         let edges: Vec<CodeEdge> = match db.graph_edges().find(filter).await {
             Ok(cursor) => collect_cursor_async(cursor).await,
-            Err(_) => Vec::new(),
+            Err(e) => {
+                tracing::warn!("Failed to fetch graph edges: {e}");
+                Vec::new()
+            }
         };
 
         // Remove disconnected nodes (no edges) to keep the graph clean
@@ -89,7 +95,7 @@ pub async fn get_graph(
 }
 
 /// GET /api/v1/graph/:repo_id/nodes — List nodes (paginated)
-#[tracing::instrument(skip_all)]
+#[tracing::instrument(skip_all, fields(repo_id = %repo_id))]
 pub async fn get_nodes(
     Extension(agent): AgentExt,
     Path(repo_id): Path<String>,
@@ -99,7 +105,10 @@ pub async fn get_nodes(
 
     let nodes: Vec<CodeNode> = match db.graph_nodes().find(filter).await {
         Ok(cursor) => collect_cursor_async(cursor).await,
-        Err(_) => Vec::new(),
+        Err(e) => {
+            tracing::warn!("Failed to fetch graph nodes: {e}");
+            Vec::new()
+        }
     };
 
     let total = nodes.len() as u64;
@@ -111,7 +120,7 @@ pub async fn get_nodes(
 }
 
 /// GET /api/v1/graph/:repo_id/communities — List detected communities
-#[tracing::instrument(skip_all)]
+#[tracing::instrument(skip_all, fields(repo_id = %repo_id))]
 pub async fn get_communities(
     Extension(agent): AgentExt,
     Path(repo_id): Path<String>,
@@ -121,7 +130,10 @@ pub async fn get_communities(
 
     let nodes: Vec<CodeNode> = match db.graph_nodes().find(filter).await {
         Ok(cursor) => collect_cursor_async(cursor).await,
-        Err(_) => Vec::new(),
+        Err(e) => {
+            tracing::warn!("Failed to fetch graph nodes for communities: {e}");
+            Vec::new()
+        }
     };
 
     let mut communities: std::collections::HashMap<u32, Vec<String>> =
@@ -161,7 +173,7 @@ pub struct CommunityInfo {
 }
 
 /// GET /api/v1/graph/:repo_id/impact/:finding_id — Impact analysis
-#[tracing::instrument(skip_all)]
+#[tracing::instrument(skip_all, fields(repo_id = %repo_id, finding_id = %finding_id))]
 pub async fn get_impact(
     Extension(agent): AgentExt,
     Path((repo_id, finding_id)): Path<(String, String)>,
@@ -183,7 +195,7 @@ pub async fn get_impact(
 }
 
 /// GET /api/v1/graph/:repo_id/search — BM25 symbol search
-#[tracing::instrument(skip_all)]
+#[tracing::instrument(skip_all, fields(repo_id = %repo_id, query = %params.q))]
 pub async fn search_symbols(
     Extension(agent): AgentExt,
     Path(repo_id): Path<String>,
@@ -204,7 +216,10 @@ pub async fn search_symbols(
         .await
     {
         Ok(cursor) => collect_cursor_async(cursor).await,
-        Err(_) => Vec::new(),
+        Err(e) => {
+            tracing::warn!("Failed to search graph nodes: {e}");
+            Vec::new()
+        }
     };
 
     let total = nodes.len() as u64;
@@ -216,7 +231,7 @@ pub async fn search_symbols(
 }
 
 /// GET /api/v1/graph/:repo_id/file-content — Read source file from cloned repo
-#[tracing::instrument(skip_all)]
+#[tracing::instrument(skip_all, fields(repo_id = %repo_id))]
 pub async fn get_file_content(
     Extension(agent): AgentExt,
     Path(repo_id): Path<String>,
@@ -278,7 +293,7 @@ pub struct FileContent {
 }
 
 /// POST /api/v1/graph/:repo_id/build — Trigger graph rebuild
-#[tracing::instrument(skip_all)]
+#[tracing::instrument(skip_all, fields(repo_id = %repo_id))]
 pub async fn trigger_build(
     Extension(agent): AgentExt,
     Path(repo_id): Path<String>,