feat: append agent stats to 6 safe output write actions

Append a collapsible markdown stats block to safe outputs that produce
human-readable content:

- create-pull-request (PR description)
- create-work-item (work item description)
- comment-on-work-item (comment body)
- add-pr-comment (PR comment body)
- create-wiki-page (wiki page content)
- update-wiki-page (wiki page content)

Stats are appended when ctx.agent_stats is populated and the per-tool
include-stats config is not explicitly false.

Example output:
<details>
<summary>🤖 Agent Stats (Daily Code Review)</summary>
| Model | claude-opus-4.5 |
| Tokens | 45,230 input / 12,450 output |
| Duration | 4m 32s |
</details>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jamesadevine

src/agent_stats.rs

@@ -147,7 +147,32 @@ impl AgentStats {
     }
 }
 
-/// Compute duration from OTel span startTime/endTime.
+/// Append agent stats markdown to a body string if stats are available
+/// and `include-stats` is not explicitly set to false in the tool config.
+///
+/// Used by safe output executors (create-pr, create-work-item, etc.)
+/// to append a collapsible stats block.
+pub fn append_stats_to_body(
+    body: &str,
+    ctx: &crate::safeoutputs::ExecutionContext,
+    tool_name: &str,
+) -> String {
+    let include = ctx
+        .tool_configs
+        .get(tool_name)
+        .and_then(|v| v.get("include-stats"))
+        .and_then(|v| v.as_bool())
+        .unwrap_or(true);
+
+    if !include {
+        return body.to_string();
+    }
+
+    match &ctx.agent_stats {
+        Some(stats) => format!("{}{}", body, stats.to_markdown()),
+        None => body.to_string(),
+    }
+}
 ///
 /// Times are `[seconds, nanoseconds]` arrays.
 fn compute_duration(span: &Value) -> f64 {

src/safeoutputs/add_pr_comment.rs

@@ -286,6 +286,11 @@ impl Executor for AddPrCommentResult {
             Some(prefix) => format!("{}{}", prefix, self.content),
             None => self.content.clone(),
         };
+        let comment_body = crate::agent_stats::append_stats_to_body(
+            &comment_body,
+            ctx,
+            "add-pr-comment",
+        );
 
         // Build the API URL
         let url = format!(

src/safeoutputs/comment_on_work_item.rs

@@ -258,8 +258,13 @@ impl Executor for CommentOnWorkItemResult {
         );
         debug!("API URL: {}", url);
 
+        let body_with_stats = crate::agent_stats::append_stats_to_body(
+            &self.body,
+            ctx,
+            "comment-on-work-item",
+        );
         let comment_body = serde_json::json!({
-            "text": self.body,
+            "text": body_with_stats,
         });
 
         info!("Sending comment to work item #{}", self.work_item_id);

src/safeoutputs/create_pr.rs

@@ -1255,8 +1255,13 @@ impl Executor for CreatePrResult {
         }
         debug!("Changes pushed successfully");
 
-        // Append provenance footer to description
+        // Append provenance footer and agent stats to description
         let description_with_footer = format!("{}{}", self.description, generate_pr_footer());
+        let description_with_stats = crate::agent_stats::append_stats_to_body(
+            &description_with_footer,
+            ctx,
+            CreatePrResult::NAME,
+        );
 
         // Create the pull request via REST API
         info!("Creating pull request");
@@ -1270,7 +1275,7 @@ impl Executor for CreatePrResult {
             "sourceRefName": source_ref,
             "targetRefName": target_ref,
             "title": effective_title,
-            "description": description_with_footer,
+            "description": description_with_stats,
             "isDraft": config.draft,
         });
 

src/safeoutputs/create_wiki_page.rs

@@ -321,7 +321,13 @@ impl Executor for CreateWikiPageResult {
             .header("Content-Type", "application/json")
             .header("If-Match", "")
             .basic_auth("", Some(token))
-            .json(&serde_json::json!({ "content": self.content }))
+            .json(&serde_json::json!({
+                "content": crate::agent_stats::append_stats_to_body(
+                    &self.content,
+                    ctx,
+                    "create-wiki-page",
+                )
+            }))
             .send()
             .await
             .context("Failed to create wiki page")?;

src/safeoutputs/create_work_item.rs

@@ -269,9 +269,14 @@ impl Executor for CreateWorkItemResult {
         debug!("API URL: {}", url);
 
         // Build the patch document for work item creation
+        let description_with_stats = crate::agent_stats::append_stats_to_body(
+            &self.description,
+            ctx,
+            "create-work-item",
+        );
         let mut patch_doc = vec![
             field_op("System.Title", &self.title),
-            field_op("System.Description", &self.description),
+            field_op("System.Description", &description_with_stats),
             // Tell Azure DevOps the description is markdown
             serde_json::json!({
                 "op": "add",

src/safeoutputs/update_wiki_page.rs

@@ -316,7 +316,13 @@ impl Executor for UpdateWikiPageResult {
             .query(&put_query)
             .header("Content-Type", "application/json")
             .basic_auth("", Some(token))
-            .json(&serde_json::json!({ "content": self.content }));
+            .json(&serde_json::json!({
+                "content": crate::agent_stats::append_stats_to_body(
+                    &self.content,
+                    ctx,
+                    "update-wiki-page",
+                )
+            }));
 
         // Provide the ETag for optimistic concurrency when updating an existing page.
         if let Some(etag) = &etag {