Turnstone container-VM: podman image -> boco qcow2 boot

Arch image with turnstone (venv), dev toolkit, rootless podman; boots
via boco (virtiofs shares, direct UID mapping for nested virtiofs).
sshd ops channel + turnstone-server as guest marvin; state (SQLite db,
config, work) on host shares; LLM via the TensorX OpenAI-compatible
gateway (https://api.tensorx.ai/v1), reachable from the guest through
both slirp layers with no relay.

configs/turnstone/config.toml.example

@@ -0,0 +1,33 @@
+# turnstone config — mounted into the VM at ~/.config/turnstone/config.toml
+# Reference: turnstone.example.toml in the upstream repo.
+
+[auth]
+# JWT signing secret. Auth is always enabled; generate once:
+#   python -c 'import secrets; print(secrets.token_hex(32))'
+jwt_secret = "CHANGE_ME_JWT_SECRET"
+
+# Models are defined here or via the admin console Models tab.
+[models.tensorx]
+# TensorX — OpenAI-compatible gateway (same backend this opencode uses).
+model = "z-ai/glm-5.3-flash"
+provider = "openai"
+base_url = "https://api.tensorx.ai/v1"
+api_key = "CHANGE_ME_TENSORX_API_KEY"
+context_window = 1000000
+
+# Self-hosted provider later? Any OpenAI-compatible endpoint reachable
+# from the guest works, e.g. llama.cpp on the LAN:
+#   [models.local]
+#   model = "..."
+#   provider = "openai"
+#   base_url = "http://<host>:<port>/v1"
+#   max_concurrency = 1
+
+[database]
+# SQLite file on the host-mounted data/ share; survives VM reboots.
+# (NOTE: for SQLite this is `path` — `url` is only used by PostgreSQL.)
+path = "/var/lib/turnstone/turnstone.db"
+
+[tools]
+# Workspace surfaced to the model (mounted from ./work on the host).
+workspace_dir = "/home/marvin/work"