Style the engine's own logs, notice enrolment while serving, say more in status

Four things from a testing pass.

`fluksio serve` printed its own lines through the root logger, which has no
handler and falls back to `INFO:fluksio.cloud.connector:...` — beside uvicorn's
aligned output it reads like something went wrong. The engine's loggers and
alembic's now use uvicorn's own handler. Named rather than configuring the
root: httpx logs every portal call at INFO and none of that is printed today.

`fluksio enroll` writes its config from another process, so an engine already
serving never learned it had been paired. It now looks for one every few
seconds and dials when it appears. `load()` rather than `exists()`, or a file
that does not parse would be restarted forever.

`fluksio status` says where the installation stands with its portal — never
paired, linked, or paired and unreachable, which is the one worth acting on.

`--seed` and `--timeout` had no help text at all. Both say what they are for
now, and the docs say what a seed is actually for: recorded on the run, part of
its input digest, and passed to an input named `seed` when the flow declares
one, so the number a run is labelled with is the one the code drew from.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019V5bsYGNxcgPs4xXmTPx69

backend/fluksio/cli.py

@@ -16,6 +16,7 @@ before any of that happens, which is what `_configure_environment` is for.
 from __future__ import annotations
 
 import argparse
+import copy
 import os
 import secrets
 import sys
@@ -285,16 +286,48 @@ def cmd_serve(args: argparse.Namespace) -> int:
 
     # One process: it holds the flow engine, and a second worker would be a
     # second engine — duplicated subscriptions, cron ticks and webhooks.
-    uvicorn.run(app, host=args.host, port=args.port, log_level=args.log_level)
+    uvicorn.run(
+        app,
+        host=args.host,
+        port=args.port,
+        log_level=args.log_level,
+        log_config=_log_config(args.log_level),
+    )
     return 0
 
 
+def _log_config(level: str) -> dict[str, Any]:
+    """Uvicorn's logging, with the engine's own loggers drawn the same way.
+
+    Without this the engine's lines go to the root logger, which has no handler
+    configured and falls back to `INFO:fluksio.cloud.connector:...` — beside
+    uvicorn's own aligned, coloured output it reads like something went wrong.
+    """
+    from uvicorn.config import LOGGING_CONFIG
+
+    config = copy.deepcopy(LOGGING_CONFIG)
+    # Named rather than configuring the root: everything else that logs — httpx
+    # on every portal call, for one — is at INFO too, and today none of it is
+    # printed at all. Styling the root would turn all of it on.
+    for name in ("fluksio", "alembic"):
+        config["loggers"][name] = {
+            "handlers": ["default"],
+            "level": level.upper(),
+            # It has a handler of its own now; propagating would print each
+            # line twice the moment anything configures the root.
+            "propagate": False,
+        }
+    return config
+
+
 def cmd_enroll(args: argparse.Namespace) -> int:
     data_dir = _data_dir(args.data_dir, args.shared)
     _prepare(data_dir)
     result = _enroll(args.portal, args.code, args.as_email)
     if result == 0:
-        _say("Start it with `fluksio serve`; it dials the portal as it comes up.")
+        # True either way round: one already serving notices within seconds,
+        # and one not yet started dials as it comes up.
+        _say("An engine already running picks this up; otherwise `fluksio serve`.")
     return result