Lint: fix errors and remove unused variables

**Motivations:**
- Ensure lint config is not degraded and fix all lint errors for pousse workflow.

**Root causes:**
- Unused variables kept with _ prefix instead of removed (_row, _questReward, _i).
- getAnimalBlockOrigin had 5 parameters (max 4).
- use of continue statement (no-continue rule).

**Correctifs:**
- ESLint config verified; no eslint-disable in codebase.
- Removed unused variable _row (biome-rules); removed dead function _questReward (quests); removed unused map param _i (state.js).
- getAnimalBlockOrigin refactored to 4 params (pos object instead of x, y).
- Replaced continue with if (cell) block in normalizeLoadedCells (state.js).
- JSDoc param names aligned with _height, _y (biome-rules).

**Evolutions:**
- (none)

**Pages affectées:**
- web/js/biome-rules.js
- web/js/quests.js
- web/js/state.js
- web/js/placement.js

web/js/biome-rules.js

@@ -8,16 +8,14 @@ export const BIOMES = ["Meadow", "Freshwater", "Ocean", "Forest", "Mountain"];
 /**
  * Base biome from grid position (5 zones by column).
  * @param {number} width
- * @param {number} height
+ * @param {number} _height
  * @param {number} x 1-based column
- * @param {number} y 1-based row
+ * @param {number} _y 1-based row
  * @returns {string}
  */
-export function getCellBiome(width, height, x, y) {
+export function getCellBiome(width, _height, x, _y) {
   const w = Math.max(1, width);
-  const h = Math.max(1, height);
   const col = Math.max(1, Math.min(w, Math.floor(x)));
-  const _row = Math.max(1, Math.min(h, Math.floor(y)));
   const t = Math.floor((col - 1) / (w / 5));
   const index = Math.min(4, Math.max(0, t));
   return BIOMES[index] ?? "Meadow";