Flag ouverture/clôture discrepancies between consecutive years

Each year's ouverture (opening balance) should match the previous
year's calculated closing balance (that year's own ouverture + every
movement dated within it). The historical spreadsheets carry real
gaps here that were preserved as-is during migration -- this surfaces
them per compte, on the ouverture row(s) they affect, the same way
the per-ligne écart column already does, rather than correcting them.

New LedgerStatsController::reconciliationOuverture() endpoint (a
single grouped SQL aggregate over ouverture vs. non-ouverture lines
per year/compte, not per-node loading) backs a small badge shown only
on the affected ouverture row(s), scoped to whichever compte that
specific row's répartition touches.

web/modules/custom/figli_compta_ledger/js/home.js

@@ -119,6 +119,16 @@
     return json.annees || [];
   }
 
+  // { "2023": { "Bachir": -0.03, ... }, ... } -- years where the actual
+  // ouverture doesn't match the previous year's calculated closing
+  // balance (that year's own ouverture + every movement dated within
+  // it). Small dataset (a handful of year boundaries), fetched once.
+  async function fetchOuvertureEcarts() {
+    const res = await fetch('/lignes/api/reconciliation-ouverture', { headers: { Accept: 'application/json' } });
+    if (!res.ok) throw new Error('/lignes/api/reconciliation-ouverture a répondu ' + res.status);
+    return res.json();
+  }
+
   async function fetchYearTotals(annee) {
     const res = await fetch('/lignes/api/totaux?annee=' + encodeURIComponent(annee), { headers: { Accept: 'application/json' } });
     if (!res.ok) throw new Error('/lignes/api/totaux a répondu ' + res.status);
@@ -182,6 +192,7 @@
         allComptes: ['Sandrine', 'Maud', 'Ouidade', 'Chloé', 'Bachir', 'Valentin', 'EXT.', 'EXT.WEB'],
         allClientsList: [],
         allYearsList: [],
+        ouvertureEcarts: {},
         filterCompte: '',
         filterClient: '',
         filterType: '',
@@ -316,6 +327,22 @@
       formatEur(v) {
         return v === null || v === undefined ? '' : EUR.format(v);
       },
+      // Écart between this ouverture row's year and the previous year's
+      // calculated closing balance -- restricted to whichever compte(s)
+      // this specific row's répartition actually touches (ouverture lines
+      // are entered one per compte, so showing every compte's écart on
+      // every row would just repeat the same list). Null if this row's
+      // compte(s) reconcile cleanly.
+      ouvertureEcart(item) {
+        if (item.type !== 'ouverture' || !item.date) return null;
+        const annee = item.date.slice(0, 4);
+        const ecarts = this.ouvertureEcarts[annee];
+        if (!ecarts) return null;
+        const relevant = Object.keys(item.parCompte).filter((c) => ecarts[c] !== undefined);
+        if (!relevant.length) return null;
+        const detail = relevant.map((compte) => compte + ' : ' + this.formatEur(ecarts[compte])).join(', ');
+        return { detail, comptes: relevant.length };
+      },
       // jj/mm/aa -- shorter than the API's ISO yyyy-mm-dd, saves column
       // width in a table already packed with 8 compte columns.
       formatDate(iso) {
@@ -638,6 +665,7 @@
       // "whatever happens to be loaded right now".
       fetchClientNames().then((names) => { this.allClientsList = names; }).catch(() => {});
       fetchYearsList().then((years) => { this.allYearsList = years; }).catch(() => {});
+      fetchOuvertureEcarts().then((ecarts) => { this.ouvertureEcarts = ecarts; }).catch(() => {});
       jQuery(document).on('dialog:afterclose', () => this.reloadWindow());
       await this.$nextTick();
       const wrap = this.$refs.tableWrap;