Add orgMemberMiddleware for org-scoped procedures

- Add OrgInfo, OrgMembership, OrgMemberContext types to context.ts
- Create org-member.ts middleware that:
  - Chains with authMiddleware
  - Takes input with org slug
  - Looks up org and verifies membership
  - Adds org and membership info to context
- Export from middlewares/index.ts and procedures/base.ts

Also simplify superuserMiddleware to use authMiddleware.concat()

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/api-server/src/context.ts

@@ -115,3 +115,34 @@ export interface SuperuserContext extends AuthenticatedContext {
   /** User with superuser privileges */
   user: SessionUser & { isSuperuser: true };
 }
+
+/**
+ * Organization info in context
+ */
+export interface OrgInfo {
+  id: number;
+  slug: string;
+  displayName: string;
+  logoUrl: string | null;
+  createdAt: Date;
+}
+
+/**
+ * User's membership in an org
+ */
+export interface OrgMembership {
+  id: number;
+  role: "owner" | "admin" | "member";
+  createdAt: Date;
+}
+
+/**
+ * Org member context for org-scoped procedures
+ * Requires user to be a member of the org
+ */
+export interface OrgMemberContext extends AuthenticatedContext {
+  /** The organization */
+  org: OrgInfo;
+  /** User's membership in the org */
+  membership: OrgMembership;
+}