Migrate transmission containers from Dockerfile to Dagger builds

Replace Dockerfiles with native container.py for both transmission and
transmission-exporter. Updates base images (Alpine 3.23, Python 3.14),
pins uv to 0.11.6 instead of :latest.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

containers/transmission-exporter/Dockerfile

@@ -1,25 +0,0 @@
-# Transmission Prometheus exporter - collect-on-scrape, no polling loop
-# uv run --script handles dependency resolution at runtime
-
-ARG CONTAINER_APP_VERSION=1.0.1
-
-FROM python:3.13-alpine3.23
-
-ARG CONTAINER_APP_VERSION
-LABEL org.opencontainers.image.title="Transmission Exporter"
-LABEL org.opencontainers.image.description="Prometheus exporter for Transmission BitTorrent client"
-LABEL org.opencontainers.image.version="${CONTAINER_APP_VERSION}"
-LABEL org.opencontainers.image.source="https://forge.eblu.me/eblume/blumeops"
-LABEL org.opencontainers.image.vendor="blumeops"
-
-COPY --from=ghcr.io/astral-sh/uv:latest /uv /usr/local/bin/uv
-
-ENV PYTHONUNBUFFERED=1
-ENV UV_CACHE_DIR=/tmp/uv-cache
-
-WORKDIR /app
-COPY exporter.py .
-
-EXPOSE 19091
-USER 65534:65534
-CMD ["uv", "run", "--script", "/app/exporter.py"]

containers/transmission-exporter/container.py

@@ -0,0 +1,37 @@
+"""Transmission Prometheus exporter — native Dagger build.
+
+Minimal collect-on-scrape exporter using uv to resolve deps at runtime.
+"""
+
+import dagger
+from dagger import dag
+
+from blumeops.containers import oci_labels
+
+VERSION = "1.0.1"
+
+PYTHON_BASE = "python:3.14-alpine3.23"
+UV_IMAGE = "ghcr.io/astral-sh/uv:0.11.6"
+
+
+async def build(src: dagger.Directory) -> dagger.Container:
+    ctr = (
+        dag.container()
+        .from_(PYTHON_BASE)
+        .with_file("/usr/local/bin/uv", dag.container().from_(UV_IMAGE).file("/uv"))
+        .with_env_variable("PYTHONUNBUFFERED", "1")
+        .with_env_variable("UV_CACHE_DIR", "/tmp/uv-cache")
+        .with_workdir("/app")
+        .with_file(
+            "/app/exporter.py", src.file("containers/transmission-exporter/exporter.py")
+        )
+        .with_exposed_port(19091)
+        .with_user("65534:65534")
+        .with_default_args(args=["uv", "run", "--script", "/app/exporter.py"])
+    )
+    return oci_labels(
+        ctr,
+        title="Transmission Exporter",
+        description="Prometheus exporter for Transmission BitTorrent client",
+        version=VERSION,
+    )