Add organizer cancel-event flow to EventList

Organizers can now cancel events directly from the event list via the
existing PATCH /events/{eventToken} API. The confirmation dialog shows
role-differentiated messaging: "Cancel event?" with a severity warning
for organizers vs. "Remove event?" for attendees. Responses 204, 409,
and 404 all result in successful removal from the local list.

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

CLAUDE.md

@@ -48,4 +48,11 @@ The following skills are available and should be used for their respective purpo
 - Autonomous work is done via Ralph Loops. See [.claude/rules/ralph-loops.md](.claude/rules/ralph-loops.md) for documentation.
 - The loop runner is `ralph.sh`. Each run lives in its own directory under `.ralph/`.
 - Run directories contain: `instructions.md` (prompt), `chief-wiggum.md` (directives), `answers.md` (human answers), `questions.md` (Ralph's questions), `progress.txt` (iteration log), `meta.md` (metadata), `run.log` (execution log).
-- Project specifications (user stories, setup tasks, personas, etc.) live in `specs/` (feature dirs) and `.specify/memory/` (cross-cutting docs).
+- Project specifications (user stories, setup tasks, personas, etc.) live in `specs/` (feature dirs) and `.specify/memory/` (cross-cutting docs).
+
+## Active Technologies
+- TypeScript 5.x, Vue 3 (Composition API) + openapi-fetch, Vue Router, Vite (018-cancel-event-list)
+- localStorage via `useEventStorage()` composable (018-cancel-event-list)
+
+## Recent Changes
+- 018-cancel-event-list: Added TypeScript 5.x, Vue 3 (Composition API) + openapi-fetch, Vue Router, Vite