Migrate frontend to Vite + Hono CopilotKit runtime

Replaces the Next.js scaffold with a Vite SPA paired with a Hono
sidecar that hosts the CopilotKit runtime and proxies AG-UI traffic
to the MAF backend. Adds dev/prod Dockerfile, .dockerignore,
.gitignore, pnpm workspace config, and updates entrypoints
(main.tsx / App.tsx / index.css / index.html) plus the service
worker accordingly.

Server middleware reconciles MAF MESSAGES_SNAPSHOT id mismatches
so post-tool-call assistant text doesn't render twice, suppresses
duplicate text emitted alongside render tools, and strips OpenAI
training-token leaks from streamed deltas.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/Dockerfile

@@ -1,7 +1,37 @@
-FROM node:20-slim
-RUN corepack enable && corepack prepare pnpm@latest --activate
+# syntax=docker/dockerfile:1.7
+
+FROM node:22-alpine AS deps
+RUN apk add --no-cache libc6-compat
 WORKDIR /app
-COPY package.json pnpm-lock.yaml ./
-RUN pnpm install --frozen-lockfile
+COPY package.json pnpm-lock.yaml* pnpm-workspace.yaml* ./
+RUN corepack enable && pnpm install --frozen-lockfile
+
+# Dev: Vite HMR on port 3000 + Hono CK server on port 3001
+FROM node:22-alpine AS dev
+RUN apk add --no-cache libc6-compat
+WORKDIR /app
+COPY --from=deps /app/node_modules ./node_modules
 COPY . .
-CMD ["pnpm", "run", "dev", "--", "--host"]
+ENV NODE_ENV=development
+EXPOSE 3000
+CMD ["sh", "-c", "corepack enable && pnpm dev"]
+
+# Build Vite SPA
+FROM node:22-alpine AS builder
+WORKDIR /app
+COPY --from=deps /app/node_modules ./node_modules
+COPY . .
+RUN corepack enable && pnpm build
+
+# Production: Hono serves dist/ + /api/copilotkit on port 3000
+FROM node:22-alpine AS runner
+RUN apk add --no-cache libc6-compat
+WORKDIR /app
+ENV NODE_ENV=production
+COPY --from=deps /app/node_modules ./node_modules
+COPY --from=builder /app/dist ./dist
+COPY server.ts package.json ./
+EXPOSE 3000
+HEALTHCHECK --interval=30s --timeout=3s --retries=3 \
+  CMD wget -qO- http://127.0.0.1:3000/api/health || exit 1
+CMD ["sh", "-c", "corepack enable && tsx server.ts"]