feat(webapp): department names in filter dropdowns

Label department selects on the ranking and explorer pages as
'94 — Val-de-Marne' via a static INSEE name map; option values keep the
bare code so filtering and numeric ordering are unchanged.

Author: glopez-dev

src/components/explorer/scatter-prix-score.tsx

@@ -12,6 +12,7 @@ import {
 } from "recharts"
 
 import { useChoropleth } from "@/hooks/useChoropleth"
+import { departementLabel } from "@/lib/departements"
 import { GAP_PRGN_HEX } from "@/lib/palettes"
 import { stratifiedSample } from "@/lib/sampling"
 import { formatEuroM2, formatScore, formatSigned } from "@/lib/format"
@@ -108,7 +109,7 @@ export function ScatterPrixScore() {
             <option value="">Tous</option>
             {depts.map((d) => (
               <option key={d} value={d}>
-                {d}
+                {departementLabel(d)}
               </option>
             ))}
           </select>

src/lib/departements.ts

@@ -0,0 +1,113 @@
+// Noms officiels des départements (INSEE), figés côté client : donnée stable,
+// évite de charger un GeoJSON juste pour libeller un <select>. Les codes
+// absents (collectivités hors périmètre DVF) retombent sur le code brut.
+
+export const DEPARTEMENT_NOMS: Record<string, string> = {
+  "01": "Ain",
+  "02": "Aisne",
+  "03": "Allier",
+  "04": "Alpes-de-Haute-Provence",
+  "05": "Hautes-Alpes",
+  "06": "Alpes-Maritimes",
+  "07": "Ardèche",
+  "08": "Ardennes",
+  "09": "Ariège",
+  "10": "Aube",
+  "11": "Aude",
+  "12": "Aveyron",
+  "13": "Bouches-du-Rhône",
+  "14": "Calvados",
+  "15": "Cantal",
+  "16": "Charente",
+  "17": "Charente-Maritime",
+  "18": "Cher",
+  "19": "Corrèze",
+  "2A": "Corse-du-Sud",
+  "2B": "Haute-Corse",
+  "21": "Côte-d'Or",
+  "22": "Côtes-d'Armor",
+  "23": "Creuse",
+  "24": "Dordogne",
+  "25": "Doubs",
+  "26": "Drôme",
+  "27": "Eure",
+  "28": "Eure-et-Loir",
+  "29": "Finistère",
+  "30": "Gard",
+  "31": "Haute-Garonne",
+  "32": "Gers",
+  "33": "Gironde",
+  "34": "Hérault",
+  "35": "Ille-et-Vilaine",
+  "36": "Indre",
+  "37": "Indre-et-Loire",
+  "38": "Isère",
+  "39": "Jura",
+  "40": "Landes",
+  "41": "Loir-et-Cher",
+  "42": "Loire",
+  "43": "Haute-Loire",
+  "44": "Loire-Atlantique",
+  "45": "Loiret",
+  "46": "Lot",
+  "47": "Lot-et-Garonne",
+  "48": "Lozère",
+  "49": "Maine-et-Loire",
+  "50": "Manche",
+  "51": "Marne",
+  "52": "Haute-Marne",
+  "53": "Mayenne",
+  "54": "Meurthe-et-Moselle",
+  "55": "Meuse",
+  "56": "Morbihan",
+  "57": "Moselle",
+  "58": "Nièvre",
+  "59": "Nord",
+  "60": "Oise",
+  "61": "Orne",
+  "62": "Pas-de-Calais",
+  "63": "Puy-de-Dôme",
+  "64": "Pyrénées-Atlantiques",
+  "65": "Hautes-Pyrénées",
+  "66": "Pyrénées-Orientales",
+  "67": "Bas-Rhin",
+  "68": "Haut-Rhin",
+  "69": "Rhône",
+  "70": "Haute-Saône",
+  "71": "Saône-et-Loire",
+  "72": "Sarthe",
+  "73": "Savoie",
+  "74": "Haute-Savoie",
+  "75": "Paris",
+  "76": "Seine-Maritime",
+  "77": "Seine-et-Marne",
+  "78": "Yvelines",
+  "79": "Deux-Sèvres",
+  "80": "Somme",
+  "81": "Tarn",
+  "82": "Tarn-et-Garonne",
+  "83": "Var",
+  "84": "Vaucluse",
+  "85": "Vendée",
+  "86": "Vienne",
+  "87": "Haute-Vienne",
+  "88": "Vosges",
+  "89": "Yonne",
+  "90": "Territoire de Belfort",
+  "91": "Essonne",
+  "92": "Hauts-de-Seine",
+  "93": "Seine-Saint-Denis",
+  "94": "Val-de-Marne",
+  "95": "Val-d'Oise",
+  "971": "Guadeloupe",
+  "972": "Martinique",
+  "973": "Guyane",
+  "974": "La Réunion",
+  "976": "Mayotte",
+}
+
+/** Libellé « 94 — Val-de-Marne » pour les <select> ; code seul si inconnu. */
+export function departementLabel(code: string): string {
+  const nom = DEPARTEMENT_NOMS[code]
+  return nom ? `${code} — ${nom}` : code
+}

src/pages/undervalued.tsx

@@ -12,6 +12,7 @@ import { PageShell } from "@/components/page-shell"
 import { LoadingHint, ErrorHint } from "@/components/status-hint"
 import { Sparkline } from "@/components/sparkline"
 import { cn } from "@/lib/utils"
+import { departementLabel } from "@/lib/departements"
 import { GAP_TEXT_NEG, GAP_TEXT_POS } from "@/lib/palettes"
 import { type ScoreProperties } from "@/lib/score"
 import { usePrixSeries } from "@/hooks/usePrixSeries"
@@ -123,7 +124,7 @@ export default function Undervalued() {
               <option value="">Tous</option>
               {deps.map((d) => (
                 <option key={d} value={d}>
-                  {d}
+                  {departementLabel(d)}
                 </option>
               ))}
             </select>