Add uv and a rootless Docker runtime on NixOS hosts

uv joins the CLI package list. Docker's daemon is now actually managed
on NixOS hosts too, in rootless mode (per-user systemd service, no
docker-group root-equivalent access), rather than leaving the runtime
entirely externally-managed as before -- the already-installed docker
CLI picks it up automatically via DOCKER_HOST. This is a documented,
narrow exception to developer-environment's client-only tools policy;
kubectl and awscli2 remain unaffected.

Archives add-uv-and-docker-runtime and syncs the new container-runtime
capability plus the narrowed developer-environment requirement into
the main specs.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HngxrvqEzq8oBEBDtrYJyB

2 files changed, 31 insertions, 0 deletions

diff --git a/openspec/changes/archive/2026-09-24-add-uv-and-docker-runtime/specs/container-runtime/spec.md b/openspec/changes/archive/2026-09-24-add-uv-and-docker-runtime/specs/container-runtime/spec.md
new file mode 100644
index 0000000..e0565c6
--- /dev/null
+++ b/openspec/changes/archive/2026-09-24-add-uv-and-docker-runtime/specs/container-runtime/spec.md
@@ -0,0 +1,19 @@
+## Purpose
+
+Provides a working, unprivileged Docker container runtime on every NixOS host built from this flake, so the already-provisioned Docker CLI tooling has a daemon to talk to without a separately-managed installation step.
+
+## ADDED Requirements
+
+### Requirement: A rootless Docker daemon runs on every NixOS host
+Every NixOS host built from this flake's shared system module SHALL run a Docker daemon in rootless mode (as the user's own account, not as root), without requiring per-host opt-in.
+
+#### Scenario: Daemon available after boot
+- **WHEN** a NixOS host built from this flake's shared system module finishes booting and the user logs in
+- **THEN** a Docker daemon is running under that user's own account, not as root
+
+### Requirement: The Docker CLI connects to the rootless daemon without manual configuration
+A user on a NixOS host built from this flake's shared system module SHALL be able to run Docker CLI commands (e.g. `docker run`, `docker build`) against the rootless daemon without manually setting `DOCKER_HOST` or other connection configuration.
+
+#### Scenario: Docker command works out of the box
+- **WHEN** a user runs a `docker` CLI command on a NixOS host built from this flake's shared system module
+- **THEN** the command reaches the rootless daemon and executes, without the user having exported `DOCKER_HOST` or written any Docker connection config themselves
diff --git a/openspec/changes/archive/2026-09-24-add-uv-and-docker-runtime/specs/developer-environment/spec.md b/openspec/changes/archive/2026-09-24-add-uv-and-docker-runtime/specs/developer-environment/spec.md
new file mode 100644
index 0000000..8a76849
--- /dev/null
+++ b/openspec/changes/archive/2026-09-24-add-uv-and-docker-runtime/specs/developer-environment/spec.md
@@ -0,0 +1,12 @@
+## MODIFIED Requirements
+
+### Requirement: Container and cloud tools are client-only
+Container and cloud-related packages provisioned by this capability SHALL provide client/CLI functionality only; they SHALL NOT attempt to provide or manage the underlying runtime or service (e.g. a Kubernetes cluster or cloud account), with one exception: Docker's runtime is managed on NixOS hosts by the separate `container-runtime` capability. Outside of NixOS hosts, and for every other tool (`kubectl`, `awscli2`), no corresponding runtime or account is installed or managed.
+
+#### Scenario: No runtime is installed or managed
+- **WHEN** a container or cloud CLI tool other than Docker is provisioned by the shared home profile
+- **THEN** no corresponding daemon, virtual machine, or account configuration is installed or managed by this capability — the tool simply connects to whatever runtime or account is already configured on the system
+
+#### Scenario: Docker's runtime is the documented exception on NixOS
+- **WHEN** the Docker CLI is provisioned by the shared home profile on a NixOS host built from this flake's shared system module
+- **THEN** a Docker runtime is available via the separate `container-runtime` capability, rather than being left entirely unmanaged