move leaked tool call recovery into build_response_message

Tool call parsing was only in runner.rs, so subconscious agents
(poc-memory agent run) never recovered leaked tool calls from
models that emit <tool_call> as content text (e.g. Qwen via Crane).

Move the recovery into build_response_message where both code paths
share it. Leaked tool calls are promoted to structured tool_calls
and the content is cleaned, so all consumers see them uniformly.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/agent/api/mod.rs

@@ -319,22 +319,49 @@ impl SseReader {
 /// Build a response Message from accumulated content and tool calls.
 /// Shared by both backends — the wire format differs but the internal
 /// representation is the same.
+///
+/// If no structured tool calls came from the API but the content
+/// contains leaked tool call XML (e.g. `<tool_call>...</tool_call>`
+/// from models that emit tool calls as text), parse them out and
+/// promote them to structured tool_calls. This way all consumers
+/// see tool calls uniformly regardless of backend.
 pub(crate) fn build_response_message(
     content: String,
     tool_calls: Vec<ToolCall>,
 ) -> Message {
+    // If the API returned structured tool calls, use them as-is.
+    if !tool_calls.is_empty() {
+        return Message {
+            role: Role::Assistant,
+            content: if content.is_empty() { None }
+                     else { Some(MessageContent::Text(content)) },
+            tool_calls: Some(tool_calls),
+            tool_call_id: None,
+            name: None,
+            timestamp: None,
+        };
+    }
+
+    // Check for leaked tool calls in content text.
+    let leaked = crate::agent::parsing::parse_leaked_tool_calls(&content);
+    if !leaked.is_empty() {
+        let cleaned = crate::agent::parsing::strip_leaked_artifacts(&content);
+        return Message {
+            role: Role::Assistant,
+            content: if cleaned.trim().is_empty() { None }
+                     else { Some(MessageContent::Text(cleaned)) },
+            tool_calls: Some(leaked),
+            tool_call_id: None,
+            name: None,
+            timestamp: None,
+        };
+    }
+
     Message {
         role: Role::Assistant,
-        content: if content.is_empty() {
-            None
-        } else {
-            Some(MessageContent::Text(content))
-        },
-        tool_calls: if tool_calls.is_empty() {
-            None
-        } else {
-            Some(tool_calls)
-        },
+        content: if content.is_empty() { None }
+                 else { Some(MessageContent::Text(content)) },
+        tool_calls: None,
         tool_call_id: None,
         name: None,
         timestamp: None,