refactor: plan timeframes use a per-day-of-week picker (like the V2 tariff)

The timeframes model was a coarse weekday/weekend split, which couldn't express
"open Saturdays" or different rules on a specific day — and it didn't match the
V2 tariff, which already has a proper per-day-of-week picker (Hën–Die).

Replace PlanTimeframes { weekday, weekend } with { days[], fromMin, toMin }: the
allowed window applies only on the selected days (0=Sun..6=Sat; empty = every
day); on unselected days the subscriber parks free. A "night plan, free
weekends" is just days [Mon..Fri] with a 20:00→08:00 window — the exact case
from before, now expressible alongside any other day combination.

outOfWindowGap reworked to the days model (per-day membership test instead of
the weekend helper); the plans editor reuses the tariff composer's Mon-first
checkbox row and the shared tariff.dow0..6 labels. No production plans carry
timeframes yet (feature shipped today), so the shape changed directly with no
migration. Unit tests updated + extended (Saturday-only, every-day, weekday
night); 81 shared tests pass. Build+lint 12/12.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

packages/shared/src/index.ts

@@ -68,23 +68,20 @@ export const ADMIN_ROLE_ID = "admin";
 export type SubscriptionPeriod = "day" | "week" | "month";
 export const SUBSCRIPTION_PERIODS: readonly SubscriptionPeriod[] = ["day", "week", "month"];
 
-/** A subscriber's allowed parking window for a day-type, as minutes-from-local-midnight
- *  (0–1439). The window is the interval [fromMin, toMin); `toMin <= fromMin` means it
- *  WRAPS past midnight (e.g. 20:00→08:00 = a night window: 1200..480). `allDay` = the
- *  whole day is allowed (no charge). An ABSENT day-window = no restriction (24/7) for
- *  that day-type. */
-export interface DayWindow {
-  readonly allDay?: boolean;
-  readonly fromMin?: number; // window opens (minutes-of-day, local)
-  readonly toMin?: number; // window closes (minutes-of-day, local)
-}
-
 /** Composed allowed-time windows on a [[subscription]] plan. A scan OUTSIDE the window
  *  is charged the transient tariff for the out-of-window minutes (the "tariff bridge").
- *  null/absent timeframes on a plan = 24/7, no charge ever. Evaluated in the site tz. */
+ *  null/absent timeframes on a plan = 24/7, no charge ever. Evaluated in the site tz.
+ *
+ *  The window applies ONLY on the selected `days` (0=Sun..6=Sat, mirroring the V2 tariff
+ *  day-of-week picker). On a NON-selected day the subscriber may park all day (no charge)
+ *  — so a "night plan" is days [Mon..Fri] with a 20:00→08:00 window, leaving the weekend
+ *  unrestricted. The window is [fromMin, toMin) minutes-of-local-midnight; `toMin ≤ fromMin`
+ *  WRAPS past midnight (a night window 20:00→08:00 = 1200..480). */
 export interface PlanTimeframes {
-  readonly weekday?: DayWindow; // Mon–Fri
-  readonly weekend?: DayWindow; // Sat–Sun
+  /** Days the window applies to (0=Sun..6=Sat). Empty/absent ⇒ every day. */
+  readonly days?: number[];
+  readonly fromMin: number; // window opens (minutes-of-day, local)
+  readonly toMin: number; // window closes (minutes-of-day, local)
   /** Tolerance (minutes) around the window edges before a charge applies. */
   readonly graceMin?: number;
   /** IANA tz the windows are wall-clock evaluated in (the site tz, captured at sale). */
@@ -1073,11 +1070,6 @@ export function localBreakdown(instantMs: number, tz: string): WallClock {
 
 // --- Subscription plan timeframes — the "tariff bridge" gap (pure, tz-aware) -------
 
-/** Is a day-of-week a weekend (Sat/Sun)? */
-function isWeekend(dow: number): boolean {
-  return dow === 0 || dow === 6;
-}
-
 /** Minute-of-day is inside the window [fromMin, toMin)? A window with toMin ≤ fromMin
  *  WRAPS past midnight (night window 20:00→08:00 ⇒ in = m ≥ 1200 OR m < 480). */
 function inWindow(m: number, fromMin: number, toMin: number): boolean {
@@ -1085,17 +1077,19 @@ function inWindow(m: number, fromMin: number, toMin: number): boolean {
 }
 
 /**
- * The out-of-window GAP for a subscriber scan, or null when the scan is in-window (or
- * the plan/day is unrestricted/all-day). This is the portion charged at the transient
- * tariff (the "tariff bridge"):
+ * The out-of-window GAP for a subscriber scan, or null when the scan is in-window (or the
+ * scan falls on a day the window does NOT apply to). This is the portion charged at the
+ * transient tariff (the "tariff bridge"):
  *   - edge "entry" (early arrival): gap = [scan, next window-OPEN] — they pay transient
  *     from arrival until their window starts (a 09:00 arrival to a 20:00 night window
  *     owes 09:00→20:00, capped by the tariff's daily cap).
  *   - edge "exit" (late departure): gap = [last window-CLOSE, scan] — they pay transient
  *     from when their window ended until they actually leave (08:00→08:45).
- * Grace widens the allowed window by `graceMin` on the relevant edge. Pure + tz-aware
- * (wall-clock in `timeframes.tz` or the passed `tz`). Minutes-of-day arithmetic anchored
- * on the scan's own local day keeps it DST-robust for the short gaps involved.
+ * The window applies only on `timeframes.days` (0=Sun..6=Sat; empty ⇒ every day); on a
+ * day NOT in the set the subscriber parks free. Grace widens the allowed window by
+ * `graceMin` on the relevant edge. Pure + tz-aware (wall-clock in `timeframes.tz` or the
+ * passed `tz`); minutes-of-day arithmetic anchored on the scan's own local day keeps it
+ * DST-robust for the short gaps involved.
  */
 export function outOfWindowGap(
   timeframes: PlanTimeframes | null | undefined,
@@ -1104,19 +1098,21 @@ export function outOfWindowGap(
   edge: "entry" | "exit",
 ): { start: string; end: string; minutes: number } | null {
   if (!timeframes) return null;
+  if (typeof timeframes.fromMin !== "number" || typeof timeframes.toMin !== "number") return null;
   const atMs = Date.parse(atISO);
   if (Number.isNaN(atMs)) return null;
   const zone = timeframes.tz || tz;
   const wall = localBreakdown(atMs, zone);
-  const day: DayWindow | undefined = isWeekend(wall.dow) ? timeframes.weekend : timeframes.weekday;
-  // No window for this day-type, or explicitly all-day ⇒ unrestricted, no charge.
-  if (!day || day.allDay) return null;
-  if (typeof day.fromMin !== "number" || typeof day.toMin !== "number") return null;
+
+  // The window applies only on the selected days; empty/absent = every day. On a day the
+  // window doesn't cover, the subscriber may park all day (no charge).
+  const days = timeframes.days;
+  if (days && days.length > 0 && !days.includes(wall.dow)) return null;
 
   const grace = Math.max(0, timeframes.graceMin ?? 0);
   const nowMin = wall.hour * 60 + wall.minute;
 
-  if (inWindow(nowMin, day.fromMin, day.toMin)) return null; // already allowed
+  if (inWindow(nowMin, timeframes.fromMin, timeframes.toMin)) return null; // already allowed
 
   // Minutes (always ≥ 0) until the window OPENS, measured forward from the scan.
   const minsUntil = (target: number) => ((target - nowMin) % 1440 + 1440) % 1440;
@@ -1125,13 +1121,13 @@ export function outOfWindowGap(
 
   if (edge === "entry") {
     // Early: charge from the scan until the window opens (minus grace tolerance).
-    let mins = minsUntil(day.fromMin) - grace;
+    const mins = minsUntil(timeframes.fromMin) - grace;
     if (mins <= 0) return null; // within grace of opening
     const end = new Date(atMs + mins * 60_000).toISOString();
     return { start: atISO, end, minutes: mins };
   }
   // Late exit: charge from when the window closed (plus grace) until the scan.
-  let mins = minsSince(day.toMin) - grace;
+  const mins = minsSince(timeframes.toMin) - grace;
   if (mins <= 0) return null; // within grace of closing
   const start = new Date(atMs - mins * 60_000).toISOString();
   return { start, end: atISO, minutes: mins };