fix(tibber): fetch forward-looking today+tomorrow via priceInfo(QUARTER_HOURLY)

priceInfoRange is a historical cursor connection whose range ends at "now": it
never returns upcoming slots. With it, the DB only ever held prices up to the
last hourly refresh, which caused two problems:

  1. The price chart could only show history up to now, never a forward curve.
  2. Worse, per-slot billing was subtly wrong. _tibber_strategy looks up the
     price via `starts_at <= t0` (nearest slot at or before the period). Because
     a period's exact 15-min slot was not fetched until the next hourly refresh
     (~1h later), intra-hour periods were billed with the PREVIOUS quarter's
     price and then locked in by the immutability guard — never corrected.

Switch to priceInfo(resolution: QUARTER_HOURLY) { today tomorrow }, which is
forward-looking AND quarter-hourly: today is always the full local day (96
slots) and tomorrow fills in once Tibber publishes day-ahead prices (picked up
by the next hourly refresh). Every 15-min slot's exact price is now in the DB
before the slot closes, so each period finds its own slot (accurate billing)
and the live current-price entity stays fresh.

Verified against the live Tibber API: fetch_price_range returns 192 points
(96 today + 96 tomorrow), spanning local today 00:00 → tomorrow 23:45, with
future slots present (previously 0).

app/integrations/tibber/client.py

@@ -30,26 +30,39 @@ logger = logging.getLogger(__name__)
 _TIBBER_API_URL = "https://api.tibber.com/v1-beta/gql"
 _DEFAULT_TIMEOUT = 15.0
 
-# GraphQL query to fetch a range of 15-minute price nodes.
-# ``priceInfoRange`` is a Relay-style cursor connection over the subscription's
-# entire available price history.  With no before/after cursor:
-#   * ``first: N`` returns the OLDEST N nodes (anchored at the subscription
-#     start date) — a fixed window that never advances, so it is WRONG for
-#     "current + upcoming" prices.
-#   * ``last: N`` returns the NEWEST N nodes (ending at the latest published
-#     slot: tomorrow 23:45 once day-ahead prices are out, else today 23:45).
-# We want the newest slots, so we use ``last``.  192 = 2 days × 24 h × 4 slots,
-# which fully covers the "today + tomorrow" window that GET /api/energy/prices
-# queries (the earliest of the 192 newest slots reaches back past today 00:00
-# UTC in either publish state).
+# GraphQL query to fetch the forward-looking today + tomorrow price curve at
+# 15-minute resolution.
+#
+# ``priceInfo(resolution: QUARTER_HOURLY)`` returns two node lists:
+#   * ``today``    — always the full current local day (96 quarter-hourly slots,
+#                    00:00 → 23:45 local), regardless of the current time.
+#   * ``tomorrow`` — the full next local day (96 slots) once Tibber publishes the
+#                    day-ahead prices (around 13:00–15:00 local); empty before that.
+#
+# This is deliberately NOT ``priceInfoRange``: that field is a historical cursor
+# connection whose range ends at "now" (it never returns future slots), so it
+# cannot supply upcoming prices.  ``priceInfo`` is forward-looking, so every
+# 15-minute slot's price is present in the DB *before* the slot closes — which is
+# what makes per-slot billing accurate (each period finds its own exact slot
+# instead of falling back to a stale earlier price) and keeps the live current-
+# price entity fresh.  The hourly refresh job re-runs this query, so tomorrow's
+# prices are picked up within an hour of publication without a restart.
 _PRICE_RANGE_QUERY = """
 {
   viewer {
     homes {
       id
       currentSubscription {
-        priceInfoRange(resolution: QUARTER_HOURLY, last: 192) {
-          nodes {
+        priceInfo(resolution: QUARTER_HOURLY) {
+          today {
+            startsAt
+            total
+            energy
+            tax
+            currency
+            level
+          }
+          tomorrow {
             startsAt
             total
             energy
@@ -236,13 +249,15 @@ def fetch_price_range(
     *,
     timeout: float = _DEFAULT_TIMEOUT,
 ) -> list[PricePoint]:
-    """Fetch a range of 15-minute price nodes from the Tibber API.
+    """Fetch the forward-looking today + tomorrow 15-minute price curve from Tibber.
 
-    Sends the ``priceInfoRange(resolution: QUARTER_HOURLY, last: 192)`` query
-    and parses every returned node into a ``PricePoint``.  ``last`` (not
-    ``first``) is used so the newest slots are returned; ``first`` would anchor
-    at the subscription start date and never advance.  The number of nodes is
-    not assumed — all returned nodes are parsed regardless of count.
+    Sends the ``priceInfo(resolution: QUARTER_HOURLY) { today tomorrow }`` query
+    and parses every node from both lists (today first, then tomorrow) into a
+    ``PricePoint``.  ``priceInfo`` is forward-looking — ``today`` is always the
+    full current local day and ``tomorrow`` is populated once Tibber publishes the
+    day-ahead prices — so upcoming slots are returned, unlike ``priceInfoRange``
+    which only reaches "now".  ``tomorrow`` may be empty (before publication); the
+    number of nodes is not assumed and all returned nodes are parsed.
 
     Parameters
     ----------
@@ -276,10 +291,15 @@ def fetch_price_range(
     home = _pick_home(homes, home_id)
 
     try:
-        nodes = home["currentSubscription"]["priceInfoRange"]["nodes"]
+        price_info = home["currentSubscription"]["priceInfo"]
+        today = price_info["today"]
+        tomorrow = price_info["tomorrow"]
     except (KeyError, TypeError) as exc:
-        raise TibberError("Tibber API response missing priceInfoRange nodes") from exc
+        raise TibberError("Tibber API response missing priceInfo today/tomorrow") from exc
 
+    # tomorrow is null/empty until Tibber publishes the day-ahead prices; treat
+    # a missing list as empty so we still return today's slots.
+    nodes = list(today or []) + list(tomorrow or [])
     return [_parse_node(node, "QUARTER_HOURLY") for node in nodes]