Rename the import package app to fluksio

A wheel whose top-level module is `app` collides with anything else in a
user's venv, so the package that is about to be published takes the name
it is published under. Only the Python package moves; the repo, the
Docker WORKDIR and the compose project keep theirs.

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

backend/fluksio/api/routes/alerts.py

@@ -0,0 +1,91 @@
+"""Alerting configuration: which failures go where."""
+
+from pathlib import Path
+from typing import Any
+
+from fastapi import APIRouter, Depends, HTTPException
+from fastapi.concurrency import run_in_threadpool
+
+from fluksio.api.deps import FlowControllerDep, get_current_user
+from fluksio.core.config import settings
+from fluksio.flow.alerts import Alert, AlertsConfig
+from fluksio.models import Message
+
+router = APIRouter(
+    prefix="/alerts", tags=["alerts"], dependencies=[Depends(get_current_user)]
+)
+
+
+def _path() -> Path:
+    return settings.ALERTS_FILE
+
+
+def read_config() -> AlertsConfig:
+    """The stored configuration, or an empty one. Blocking."""
+    path = _path()
+    if not path.exists():
+        return AlertsConfig()
+    try:
+        return AlertsConfig.model_validate_json(path.read_text())
+    except Exception:
+        # A hand-edited file that no longer parses must not stop the engine.
+        return AlertsConfig()
+
+
+def write_config(config: AlertsConfig) -> None:
+    """Blocking."""
+    path = _path()
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_text(config.model_dump_json(indent=2))
+
+
+@router.get("/config", response_model=AlertsConfig)
+async def read_alerts_config() -> Any:
+    """What the engine alerts on, and where it sends it."""
+    return await run_in_threadpool(read_config)
+
+
+@router.put("/config", response_model=AlertsConfig)
+async def save_alerts_config(body: AlertsConfig, controller: FlowControllerDep) -> Any:
+    """Replace the configuration. Takes effect immediately."""
+    known = {channel.name for channel in body.channels}
+    for rule in body.rules:
+        missing = [name for name in rule.channels if name not in known]
+        if missing:
+            raise HTTPException(
+                status_code=422,
+                detail=f"No channel named {', '.join(repr(m) for m in missing)}",
+            )
+
+    await run_in_threadpool(write_config, body)
+    if controller.alerts is not None:
+        controller.alerts.config = body
+    return body
+
+
+@router.post("/test/{channel_name}", response_model=Message)
+async def test_channel(channel_name: str, controller: FlowControllerDep) -> Any:
+    """Send one alert, to prove the channel works before relying on it."""
+    if controller.alerts is None:
+        raise HTTPException(status_code=503, detail="Alerting is not running")
+
+    config = controller.alerts.config
+    channel = next((c for c in config.channels if c.name == channel_name), None)
+    if channel is None:
+        raise HTTPException(status_code=404, detail=f"No channel '{channel_name}'")
+
+    try:
+        await controller.alerts.send(
+            channel,
+            Alert(
+                title="Fluksio test alert",
+                body="If you are reading this, the channel works.",
+                severity="warning",
+            ),
+            raise_on_error=True,
+        )
+    except Exception as exc:
+        # Whatever the sender said, verbatim: it is the only clue the operator
+        # has about why the channel does not work.
+        raise HTTPException(status_code=502, detail=str(exc) or type(exc).__name__)
+    return Message(message=f"Sent a test alert through '{channel_name}'")