feat(sdk): add plugin activationScope (app/project)

Manifests can now declare activationScope to defer activation until a
project is focused, instead of always activating at app bootstrap.

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

src/index.ts

@@ -1,4 +1,5 @@
 export type {
+  IdeAPluginActivationScope,
   IdeAPluginCapability,
   IdeAPluginManifest,
   IdeAPluginEngineConstraints,

src/manifest.ts

@@ -9,6 +9,10 @@ export interface IdeAPluginManifest {
   publisher?: string;
   engines?: IdeAPluginEngineConstraints;
   capabilities?: IdeAPluginCapability[];
+  /**
+   * Defaults to "app". Use "project" when activate(ctx) requires a focused project.
+   */
+  activationScope?: IdeAPluginActivationScope;
   contributes?: {
     menus?: IdeAPluginTopLevelMenuContribution[];
     menuItems?: IdeAPluginMenuItemContribution[];
@@ -19,6 +23,8 @@ export interface IdeAPluginManifest {
 
 export type IdeAPluginCapability = "ui" | "mcp" | "tooling";
 
+export type IdeAPluginActivationScope = "app" | "project";
+
 export interface IdeAPluginEngineConstraints {
   idea?: string;
 }
@@ -100,6 +106,7 @@ export function validatePluginManifest(input: unknown): PluginManifestValidation
 
   validateEngines(input.engines, errors);
   validateCapabilities(input.capabilities, errors);
+  validateActivationScope(input.activationScope, errors);
   validateContributes(input.contributes, errors);
 
   if (errors.length > 0) {
@@ -151,6 +158,16 @@ function validateCapabilities(value: unknown, errors: string[]): void {
   });
 }
 
+function validateActivationScope(value: unknown, errors: string[]): void {
+  if (value === undefined) {
+    return;
+  }
+
+  if (value !== "app" && value !== "project") {
+    errors.push("activationScope must be \"app\" or \"project\" when provided");
+  }
+}
+
 function validateContributes(value: unknown, errors: string[]): void {
   if (value === undefined) {
     return;