Add Cloud Agent development environment for Berd

.cursor/Dockerfile

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+FROM ubuntu:24.04
+
+ENV DEBIAN_FRONTEND=noninteractive
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends \
+        build-essential \
+        ca-certificates \
+        cmake \
+        curl \
+        g++ \
+        git \
+        jq \
+        libayatana-appindicator3-dev \
+        libgtk-3-dev \
+        librsvg2-dev \
+        libssl-dev \
+        libstdc++-14-dev \
+        libwebkit2gtk-4.1-dev \
+        pkg-config \
+        python3 \
+        sudo \
+        unzip \
+        xvfb \
+    && rm -rf /var/lib/apt/lists/*
+
+# Hermit and the repo checkout expect a normal non-root user.
+RUN useradd -m -s /bin/bash ubuntu \
+    && echo "ubuntu ALL=(ALL) NOPASSWD:ALL" >> /etc/sudoers
+
+USER ubuntu
+WORKDIR /home/ubuntu

.cursor/environment.json

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+{
+  "name": "Berd",
+  "build": {
+    "dockerfile": "Dockerfile",
+    "context": ".."
+  },
+  "user": "ubuntu",
+  "install": "./scripts/cloud-agent-install.sh"
+}

scripts/cloud-agent-install.sh

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+#!/usr/bin/env bash
+set -euo pipefail
+
+repo_root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$repo_root"
+
+# Pin tool versions to the repo's Hermit environment (just, node, pnpm, rust).
+source "$repo_root/bin/activate-hermit"
+
+export PATH="$repo_root/bin:$PATH"
+export CI="${CI:-true}"
+
+# Skip git hooks in cloud agents; they are not needed for validation workflows.
+just _setup-dev-deps
+GOOSE_DEV_MODE=required GOOSE_BUILD_PROFILE=debug ./scripts/ensure-local-goose.sh