Rename path parameter {token} to {eventToken} in OpenAPI spec

Aligns the path parameter naming with the value object convention
used throughout the codebase (eventToken, rsvpToken, organizerToken).

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

backend/src/main/resources/openapi/api.yaml

@@ -37,7 +37,7 @@ paths:
               schema:
                 $ref: "#/components/schemas/ValidationProblemDetail"
 
-  /events/{token}/rsvps/{rsvpToken}:
+  /events/{eventToken}/rsvps/{rsvpToken}:
     delete:
       operationId: cancelRsvp
       summary: Cancel RSVP
@@ -47,7 +47,7 @@ paths:
       tags:
         - events
       parameters:
-        - name: token
+        - name: eventToken
           in: path
           required: true
           schema:
@@ -69,14 +69,14 @@ paths:
         "500":
           description: Internal server error
 
-  /events/{token}/rsvps:
+  /events/{eventToken}/rsvps:
     post:
       operationId: createRsvp
       summary: Submit an RSVP for an event
       tags:
         - events
       parameters:
-        - name: token
+        - name: eventToken
           in: path
           required: true
           schema:
@@ -115,14 +115,14 @@ paths:
               schema:
                 $ref: "#/components/schemas/ProblemDetail"
 
-  /events/{token}/attendees:
+  /events/{eventToken}/attendees:
     get:
       operationId: getAttendees
       summary: Get attendee list for an event (organizer only)
       tags:
         - events
       parameters:
-        - name: token
+        - name: eventToken
           in: path
           required: true
           schema:
@@ -156,14 +156,14 @@ paths:
               schema:
                 $ref: "#/components/schemas/ProblemDetail"
 
-  /events/{token}:
+  /events/{eventToken}:
     get:
       operationId: getEvent
       summary: Get public event details by token
       tags:
         - events
       parameters:
-        - name: token
+        - name: eventToken
           in: path
           required: true
           schema: