Rebuild auth on Keycloak OIDC, fix rootless Ansible deploy

Replaces the single shared HTTP Basic service-account credential (which
caused a production outage from a username mismatch) with per-user login:
Keycloak (already running on this VM for gcnm, now also fronted on
auth.friessn.de with its own "homekeeper" realm) authenticates the user
once via the landing page, FastAPI verifies the OIDC id_token and mints
its own signed session JWT as a cookie, and both Shiny apps forward that
per-session token as a Bearer credential instead of a static shared one.
Authorization is a simple ALLOWED_USERS allowlist; the old auth.users
table and bcrypt seeding are gone entirely.

Also carries forward the in-progress rootless Podman/Quadlet migration
(gitea, homekeeper, podman roles) and fixes a pre-existing bug where
each role's handlers were malformed inside tasks/main.yml instead of
their own handlers/main.yml, which broke ansible-playbook entirely.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FbiCdckkTX2HyAkyi1R39d

api/app/routers/auth.py

@@ -0,0 +1,116 @@
+import os
+import secrets
+from urllib.parse import urlencode
+
+import httpx
+from fastapi import APIRouter, Depends, HTTPException, Query, Request
+from fastapi.responses import RedirectResponse
+
+from app.auth import (
+    COOKIE_NAME,
+    OIDC_CLIENT_ID,
+    OIDC_CLIENT_SECRET,
+    SESSION_TTL_SECONDS,
+    get_current_user,
+    is_allowed_user,
+    mint_session_jwt,
+    oidc_config,
+    verify_oidc_id_token,
+)
+
+router = APIRouter()
+
+ENV = os.getenv("ENV", "production")
+COOKIE_SECURE = os.getenv("COOKIE_SECURE", "true").lower() == "true"
+PUBLIC_BASE_URL = os.getenv("PUBLIC_BASE_URL", "http://localhost").rstrip("/")
+STATE_COOKIE = "hk_oauth_state"
+CALLBACK_PATH = "/api/v1/auth/callback"
+
+
+def _set_session_cookie(resp, token: str):
+    resp.set_cookie(
+        key=COOKIE_NAME,
+        value=token,
+        max_age=SESSION_TTL_SECONDS,
+        path="/",
+        httponly=True,
+        secure=COOKIE_SECURE,
+        samesite="lax",
+    )
+
+
+@router.get("/login")
+def login():
+    config = oidc_config()
+    state = secrets.token_urlsafe(24)
+    params = {
+        "client_id": OIDC_CLIENT_ID,
+        "redirect_uri": f"{PUBLIC_BASE_URL}{CALLBACK_PATH}",
+        "response_type": "code",
+        "scope": "openid profile",
+        "state": state,
+    }
+    resp = RedirectResponse(f"{config['authorization_endpoint']}?{urlencode(params)}")
+    resp.set_cookie(STATE_COOKIE, state, max_age=600, path="/", httponly=True, secure=COOKIE_SECURE, samesite="lax")
+    return resp
+
+
+@router.get("/callback")
+def callback(request: Request, code: str | None = Query(None), state: str | None = Query(None), error: str | None = Query(None)):
+    if error:
+        raise HTTPException(status_code=400, detail=f"OIDC error: {error}")
+
+    expected_state = request.cookies.get(STATE_COOKIE)
+    if not code or not state or not expected_state or state != expected_state:
+        raise HTTPException(status_code=400, detail="Invalid OAuth state")
+
+    config = oidc_config()
+    token_resp = httpx.post(
+        config["token_endpoint"],
+        data={
+            "grant_type": "authorization_code",
+            "code": code,
+            "redirect_uri": f"{PUBLIC_BASE_URL}{CALLBACK_PATH}",
+            "client_id": OIDC_CLIENT_ID,
+            "client_secret": OIDC_CLIENT_SECRET,
+        },
+        timeout=10,
+    )
+    token_resp.raise_for_status()
+    id_token = token_resp.json()["id_token"]
+    claims = verify_oidc_id_token(id_token)
+    username = claims.get("preferred_username") or claims.get("name")
+
+    if not username or not is_allowed_user(username):
+        raise HTTPException(status_code=403, detail=f"User '{username}' is not allowed to access Homekeeper")
+
+    resp = RedirectResponse("/")
+    _set_session_cookie(resp, mint_session_jwt(username))
+    resp.delete_cookie(STATE_COOKIE, path="/")
+    return resp
+
+
+@router.get("/logout")
+def logout():
+    resp = RedirectResponse("/")
+    resp.delete_cookie(COOKIE_NAME, path="/")
+    return resp
+
+
+@router.get("/me")
+def me(username: str = Depends(get_current_user)):
+    return {"username": username}
+
+
+@router.get("/dev-login")
+def dev_login(username: str = Query(...)):
+    """Local-dev-only bypass: mints a session for `username` without touching
+    the OIDC provider. Only reachable when ENV=development."""
+    if ENV != "development":
+        raise HTTPException(status_code=404)
+    if not is_allowed_user(username):
+        raise HTTPException(status_code=403, detail=f"User '{username}' is not in ALLOWED_USERS")
+
+    resp = RedirectResponse("/")
+    _set_session_cookie(resp, mint_session_jwt(username))
+    return resp