Add the fluksio CLI: serve, enroll, worker

`pip install fluksio && fluksio serve` on a machine with no Docker, no
database and no configuration — which is the case this is for: a node on
a cluster where ports cannot be opened. It makes its data directory, its
key and an admin account, prints the password once, and serves. Pairing
is `fluksio enroll <code> --portal …`, doing what the Settings screen
does through the same function, before the engine starts and without one
running — a machine nobody can route to has no browser pointed at it
either. The portal serves the dashboard, so nothing is served here.

Two things had to give way. `fastapi[standard]` pulls a cloud CLI that
wants sentry-sdk 2.x while we pinned below it — no pip resolution
existed, so the pin is lifted, which the comment beside it had been
waiting for and which also lets the Python cap go. And `uv` is now a
dependency rather than something to find on PATH: the Modules screen is
how a data scientist installs torch, and it was quietly falling back to
the engine's own interpreter.

The CLI imports nothing from the engine before it has set DATA_DIR — the
settings are built on the first import of core.config, and reaching it
early put the database in the working directory. There is a test for
that now, because the failure is silent.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Makefile

@@ -4,7 +4,7 @@
 
 .PHONY: dev-utils dev dev-local up down update install dev-backend dev-frontend \
         generate-client seed-example seed-demo seed-house seed-aircon seed-hosted-demo test test-backend test-frontend soak bench-startup lint lint-backend \
-        lint-frontend format-frontend umami clean help
+        lint-frontend format-frontend umami build clean help
 
 COMPOSE_ROOT := $(CURDIR)
 # Explicit project name keeps this stack isolated from the sibling website
@@ -161,6 +161,9 @@ bench-startup:  ## Time submitting a run (BENCH_ARGS="--kedro ../some/kedro/proj
 
 # ── Linting ───────────────────────────────────────────────────────
 
+build:  ## Build the fluksio and fluksio-worker wheels into dist/
+	uv build --all-packages --out-dir dist
+
 lint: lint-backend lint-frontend  ## Run all linters
 
 lint-backend:  ## Lint backend with ruff + mypy