Add initial KioskCore and API endpoint for data analysis

- Created a new CSS file for kiosk styles, defining variables, typography, and layout for cards and toolbars.
- Implemented new routes for data anlaysis page

api/src/storage/influx.js

@@ -60,6 +60,64 @@ async function query(bucket, relativeTime, measurement, sensor, field) {
 
 }
 
+const sessionBucket = process.env.INFLX_BUCKET || 'logs';
+
+/**
+ * Query storica per una sessione di registrazione.
+ * @param {string} sensor - nome sensore
+ * @param {string} session - session_id (tag InfluxDB)
+ * @param {string} since - ISO timestamp o duration (es. "-30d")
+ * @param {string|null} until - ISO timestamp fine (opzionale)
+ * @returns {Promise<Array<Object>>}
+ */
+async function querySessionHistory(sensor, session, since, until = null) {
+    const rangeStr = until ? `start: ${since}, stop: ${until}` : `start: ${since}`;
+    const fluxQuery = `
+        from(bucket: "${sessionBucket}")
+            |> range(${rangeStr})
+            |> filter(fn: (r) => r._measurement == "logs")
+            |> filter(fn: (r) => r.sensor == "${sensor}")
+            |> filter(fn: (r) => r.session == "${session}")
+            |> pivot(rowKey:["_time"], columnKey: ["_field"], valueColumn: "_value")
+            |> sort(columns: ["_time"])
+    `;
+    const rows = [];
+    return new Promise((resolve, reject) => {
+        querying.queryRows(fluxQuery, {
+            next(row, tableMeta) { rows.push(tableMeta.toObject(row)); },
+            error: reject,
+            complete() { resolve(rows); },
+        });
+    });
+}
+
+/**
+ * Esporta i dati di una sessione come stringa CSV.
+ * @param {string} sensor
+ * @param {string} session
+ * @param {string} since
+ * @param {string|null} until
+ * @returns {Promise<string>}
+ */
+async function exportSessionCSV(sensor, session, since, until = null) {
+    const rows = await querySessionHistory(sensor, session, since, until);
+    if (rows.length === 0) return '';
+    const metaKeys = new Set(['result', 'table', '_start', '_stop', '_measurement', 'sensor', 'session', '']);
+    const fieldNames = new Set();
+    for (const row of rows) {
+        for (const key of Object.keys(row)) {
+            if (!metaKeys.has(key) && key !== '_time') fieldNames.add(key);
+        }
+    }
+    const fields = Array.from(fieldNames).sort();
+    const header = ['timestamp', ...fields].join(',');
+    const csvRows = rows.map(row => {
+        const values = fields.map(f => { const v = row[f]; return (v == null) ? '' : v; });
+        return [row._time || '', ...values].join(',');
+    });
+    return header + '\n' + csvRows.join('\n') + '\n';
+}
+
 async function checkInflux() {
     try {
         const result = await querying.collectRows(
@@ -78,9 +136,11 @@ async function checkInflux() {
 }
 
 module.exports = {
-    write:append,
+    write: append,
     writeBatch,
     query,
+    querySessionHistory,
+    exportSessionCSV,
     checkInflux
 }