fix(reports/legacy): exclude expired credits; confirm monthly price model

Reviewed against docs/archive/LEGACY-ACCOUNTING-ANALYSIS.md (the migration
audit) which surfaced two things to check in the overpriced-internet report:

1. service.payment_recurrence (0=annual, 2=monthly, 5=semestrial...) —
   checked whether per-cycle prices needed /N normalization. They do NOT:
   verified a semestrial FTTH1500I carries product.price=109.95, identical
   to the monthly one (billed 6×109.95 every 6 months). Per §6.1
   "prix = quantité × prix_unitaire", product.price is already the monthly
   unit price. The original monthly logic was correct — no division. The
   SKU-LIKE-'%ANN' /12 special-case stays (true annual plans where price
   IS the yearly amount, e.g. FTTH_ANN @ 480$/yr).

2. Promo credits carry an actif_until end date (§10). A discount line whose
   actif_until is past no longer reduces today's bill, so counting it
   understates what the client actually pays. Now excluded.

   NULL-safety: the exclusion needs an explicit `actif_until IS NOT NULL`
   guard — without it, `NOT (price<0 AND actif_until>0 AND actif_until<now)`
   evaluates to NULL for permanent credits (actif_until NULL), which SQL
   treats as not-true and silently DROPS every permanent credit line. That
   briefly inflated the residential count to 3330; with the guard it's a
   correct 1000 (vs 983 before — +17 addresses whose only sub-90 reason was
   a now-expired credit).

Net effect: the report reflects the *current* real monthly Internet bill.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

services/targo-hub/lib/legacy-reports.js

@@ -22,15 +22,26 @@
  *
  *   Effective monthly price of a service line:
  *     base   = service.hijack=1 ? service.hijack_price : product.price
- *     // Annual plans (SKU ends in "ANN", e.g. FTTH_ANN @ 480$/yr) are
+ *     // product.price is ALREADY the monthly unit price regardless of the
- *     // normalized to a monthly equivalent so the threshold compares apples
+ *     // service's billing frequency — a semestrial FTTH1500I has price
- *     // to apples — otherwise a $480/yr (=$40/mo) plan falsely shows as $480.
+ *     // 109.95 (same as the monthly one) and is billed 6×109.95 every 6
+ *     // months. Verified against the legacy billing logic (LEGACY-
+ *     // ACCOUNTING-ANALYSIS.md §6.1: "prix = quantité × prix_unitaire").
+ *     // So we do NOT divide by service.payment_recurrence.
+ *     // The one exception: true annual plans (SKU ends in "ANN", e.g.
+ *     // FTTH_ANN @ 480$/yr where price IS the yearly amount) → normalize /12.
  *     monthly = base / (sku LIKE '%ANN' ? 12 : 1)
  *
  *   Only recurring lines count: product.price_recurr_type = 1. Type 0 is
  *   one-time charges (equipment, installation) which don't belong on a
  *   recurring monthly bill.
  *
+ *   Expired credits excluded: a discount line (price<0) whose service
+ *   actif_until is in the past no longer reduces the real bill — counting
+ *   it would understate what the client actually pays today. (Per
+ *   LEGACY-ACCOUNTING-ANALYSIS.md §10: promo credits carry an actif_until
+ *   end date.)
+ *
  *   Internet product categories:
  *     32 Mensualités fibre, 4 Mensualités sans-fil, 23 Internet camping
  *     (add-ons) 16 Téléch. supp, 17 IP fixe, 21 Location point-à-point
@@ -106,6 +117,7 @@ function buildQuery (url) {
     JOIN product  p ON p.id = s.product_id
     WHERE p.category IN (${catPlaceholders})
       AND p.price_recurr_type = 1
+      AND NOT (p.price < 0 AND s.actif_until IS NOT NULL AND s.actif_until > 0 AND s.actif_until < UNIX_TIMESTAMP())
       ${commercialClause}
     GROUP BY d.id
     HAVING net_internet > ?