feat(tariff): stepped ("up-to") pricing mode — total-by-duration

Owners often state rates as a total-by-duration matrix (0-1h=200, 0-3h=500,
0-6h=800, 0-9h=900, 0-12h=1000) that the marginal hourly ladder can't express
(the ladder sums per-increment rates; this is cumulative totals at thresholds).
Add STEPPED as a third pricing mode alongside the ladder and flat.

- @parking/shared: TariffStep {uptoMin, totalMinor} + a `steps[]` field on V1
  structures and V2 cards (mutually exclusive with blocks/flatMinor). steppedFee():
  smallest tier with uptoMin >= duration wins (INCLUSIVE boundary), the top tier
  repeats as a per-day cap; wired into computeFeeV1 + computeFeeV2 (V2 default card
  only — a whole-stay total can't be sliced per-increment by a windowed card).
  Validation: ascending uptoMin, non-negative totals, no daily-cap-with-steps,
  steps-only-on-default. priceSession/quote/booth/Lab price it via the shared core.
- Composer UI: a "By duration (up-to)" mode with an up-to/total table (base card
  only). i18n modeStepped/steppedHint/stepUpTo/stepTotal/addStep (sq+en).
- 8 new unit tests incl. the exact owner matrix, multi-day repeat, overstay, and
  validation (53 pass). Verified end-to-end via the UI: authored + published the
  matrix, Tariff Lab prices it exactly (3h->500, 6h->800, 12h->1000, 2d->2000).

Wiki: tariff (three pricing modes + stepped semantics), log.

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

wiki/concepts/tariff.md

@@ -63,6 +63,44 @@ code. All amounts are **integer minor units** in the tariff's currency.
 > the owner must compose + publish one before the lot can charge (until then: free, or gated —
 > operator policy, see Open).
 
+### Three pricing modes (per card / per V1 structure)
+
+A card's body is **one of three mutually-exclusive shapes** — `flatMinor`, `blocks`, or `steps`:
+
+1. **Hourly ladder (`blocks`)** — the model above: a **marginal per-increment** rate that the engine
+   *sums* across increments. "Each next hour costs X." Daily-cap and multi-day reset apply.
+2. **Flat (`flatMinor`)** — one rate per increment (a one-block ladder).
+3. **Stepped / "up-to" (`steps`)** — *added 2026-06-20.* A **total-by-duration** table the owner
+   enters verbatim — the opposite of marginal: each row is the **cumulative TOTAL** for a stay within
+   that tier. Needed because owners think in totals, and many real cards (flat-day, airport) are
+   stated this way and **cannot** be expressed as a marginal ladder.
+
+```jsonc
+"steps": [                      // each row: total price for a stay UP TO uptoMin (inclusive)
+  { "uptoMin": 60,  "totalMinor": 200 },   // 0–1h  → 200
+  { "uptoMin": 180, "totalMinor": 500 },   // 0–3h  → 500
+  { "uptoMin": 360, "totalMinor": 800 },   // 0–6h  → 800
+  { "uptoMin": 540, "totalMinor": 900 },   // 0–9h  → 900
+  { "uptoMin": 720, "totalMinor": 1000 }   // 0–12h → 1000
+]
+```
+
+**Stepped semantics** (decided with the user, 2026-06-20):
+- The **smallest tier whose `uptoMin ≥ duration`** wins; the boundary is **inclusive** (`≤`) — a stay
+  of exactly 3h00m costs the 3h tier (500), not the next.
+- Beyond the **largest threshold**, that tier's total is the **per-day price** (a daily-cap repeat):
+  a 13h stay within one rolling day = 1000 (the top total is the day's ceiling), and a 25h stay =
+  1000 (day 1) + the stepped ladder for the remaining 1h on day 2 = 1200.
+- A `steps` table **replaces** the `blocks` ladder and **forbids `dailyCapMinor`** (the top tier IS
+  the per-day cap). In V2 it is allowed **only on the `defaultCard`** — a whole-stay total can't be
+  sliced per-increment by a windowed card, so windowed/stepped don't compose.
+- Validation: ≥1 row, strictly-ascending positive `uptoMin`, non-negative integer totals (totals
+  need not be monotonic — an owner *may* price a longer stay cheaper).
+
+The owner authors this in the composer ("By duration (up-to)" mode) as an *up-to N hours / total*
+table; the [[#tariff-lab-simulator-as-built-2026-06-20|Tariff Lab]] previews the curve. Verified
+end-to-end: the matrix above publishes and prices exactly (30m→200, 3h→500, 6h→800, 12h→1000, 2d→2000).
+
 **Lost ticket** is not just the flat `lostTicketMinor`: the admin may **override with an arbitrary
 amount** at the moment (operator judgement — establish entry time from [[opencv-anpr-service|plate]]
 capture/CCTV and charge real duration, or apply a set penalty). The configured flat fee is the

wiki/log.md

@@ -1022,3 +1022,21 @@ incl. the ticket-1245791632490 overstay-not-zero regression (40 tests pass). Ver
 live via the real UI: a 3h stay → ALL 3,000, curve shows the daily cap flattening at
 6h and multi-day stepping; ticket-load returned a real session. Build+lint green.
 Updated [[tariff]] + [[booth-exit-flow]].
+
+## [2026-06-20] feat | Stepped ("up-to") tariff mode — total-by-duration pricing
+
+The owner needed a total-by-duration matrix (0-1h=200, 0-3h=500, 0-6h=800, 0-9h=900,
+0-12h=1000) the marginal hourly ladder CANNOT express (ladder sums per-increment
+rates; this is cumulative totals at thresholds). Added STEPPED pricing as a third
+mode alongside ladder + flat. New TariffStep{uptoMin,totalMinor} + steps[] on V1
+structures and V2 cards (mutually exclusive w/ blocks/flatMinor). Engine steppedFee():
+smallest tier with uptoMin>=duration wins (INCLUSIVE <=), top tier repeats as per-day
+cap; wired into computeFeeV1 + computeFeeV2 (V2 defaultCard only — a whole-stay total
+can't be sliced by a windowed card). Validation: ascending uptoMin, non-neg totals, no
+dailyCap-with-steps, steps-only-on-default. priceSession/quote/booth/Lab all price it
+via the shared core (no extra wiring). Composer UI: "By duration (up-to)" radio +
+up-to/total table (base card only); i18n modeStepped/steppedHint/stepUpTo/stepTotal/
+addStep (sq+en). 8 new unit tests incl. the exact owner matrix + multi-day + overstay
++ validation (53 pass). VERIFIED end-to-end via the real UI: authored the matrix in the
+composer, published, Tariff Lab priced it exactly (3h->500, 6h->800, 12h->1000,
+2d->2000). Build+lint green. Updated [[tariff]].