story-kit: merge 153_bug_auto_assign_broken_after_stage_field_was_added_to_agent_config

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

server/src/config.rs

@@ -45,6 +45,11 @@ pub struct AgentConfig {
     pub max_budget_usd: Option<f64>,
     #[serde(default)]
     pub system_prompt: Option<String>,
+    /// Pipeline stage this agent belongs to. Supported values: "coder", "qa",
+    /// "mergemaster", "other". When set, overrides the legacy name-based
+    /// detection used by `pipeline_stage()`.
+    #[serde(default)]
+    pub stage: Option<String>,
     /// Inactivity timeout in seconds for the PTY read loop.
     /// If no output is received within this duration, the agent process is killed
     /// and marked as Failed. Default: 300 (5 minutes). Set to 0 to disable.
@@ -99,6 +104,7 @@ impl Default for ProjectConfig {
                 max_turns: None,
                 max_budget_usd: None,
                 system_prompt: None,
+                stage: None,
                 inactivity_timeout_secs: default_inactivity_timeout_secs(),
             }],
         }