feat(plugins): load activation scope from plugin manifest

Plugins can now declare activationScope ("app" | "project") in their
manifest; loader/runtime honor it to defer activation of project-scoped
plugins until a project is focused instead of activating everything at
app bootstrap. Bumps sdk/IdeaSDK to the commit that adds the field.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

crates/domain/src/plugin.rs

@@ -288,6 +288,22 @@ pub enum PluginCapability {
     Tooling,
 }
 
+/// Manifest-declared runtime activation scope.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "lowercase")]
+pub enum PluginActivationScope {
+    /// Activate at app bootstrap, without requiring a focused project.
+    App,
+    /// Wait until a project is focused before the first activation.
+    Project,
+}
+
+impl Default for PluginActivationScope {
+    fn default() -> Self {
+        Self::App
+    }
+}
+
 /// Plugin command id.
 #[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
 #[serde(transparent)]
@@ -495,6 +511,9 @@ pub struct PluginManifest {
     /// Capabilities.
     #[serde(default)]
     pub capabilities: Vec<PluginCapability>,
+    /// Activation scope. Missing in older manifests means app-level activation.
+    #[serde(default)]
+    pub activation_scope: PluginActivationScope,
     /// Contributions.
     pub contributes: PluginContributionSet,
 }
@@ -693,4 +712,13 @@ mod tests {
             serde_json::json!(["ui", "mcp", "tooling"])
         );
     }
+
+    #[test]
+    fn plugin_activation_scope_defaults_to_app_and_serializes_public_names() {
+        assert_eq!(PluginActivationScope::default(), PluginActivationScope::App);
+        assert_eq!(
+            serde_json::to_value(PluginActivationScope::Project).unwrap(),
+            serde_json::json!("project")
+        );
+    }
 }