feat: prepare self-contained open-source release

.env.example

@@ -0,0 +1,17 @@
+# Copy this file to .env and fill only the services you use.
+# .env is ignored by Git and loaded automatically by the managed launcher.
+
+# Optional repository-local SearXNG extension. Both values are required when enabled.
+SEARXNG_URL=
+SEARXNG_TOKEN=
+
+# Optional higher Context7 quota. Context7 also works at its public unauthenticated limit.
+CONTEXT7_API_KEY=
+
+# Optional built-in model-provider credentials. The Web UI can also configure providers.
+ANTHROPIC_API_KEY=
+OPENAI_API_KEY=
+GEMINI_API_KEY=
+
+# Optional: move mutable runtime data while retaining the same isolation model.
+# PI_AGENT_DATA_DIR=D:\path\to\pi-agent-data