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/backend/src/dto.rs

@@ -242,6 +242,8 @@ pub struct PluginRuntimePluginDto {
     pub content_hash: String,
     /// Public manifest capabilities.
     pub capabilities: Vec<domain::PluginCapability>,
+    /// Manifest-declared activation scope.
+    pub activation_scope: domain::PluginActivationScope,
     /// Contributions.
     pub contributes: domain::PluginContributionSet,
 }
@@ -269,6 +271,7 @@ impl From<application::PluginRuntimePlugin> for PluginRuntimePluginDto {
             icon_url: value.icon_url,
             content_hash: value.content_hash,
             capabilities: value.capabilities,
+            activation_scope: value.activation_scope,
             contributes: value.contributes,
         }
     }