Build container image in CI, bake in datasets, configure auth via env

- Dockerfile bakes the app and every CSV in data/ into an nginx image
- UI discovers data/*.csv via nginx JSON autoindex and offers a
  dropdown when there is more than one dataset
- docker-entrypoint.d/40-basic-auth.sh creates .htpasswd from
  BASIC_AUTH_USER / BASIC_AUTH_PASSWORD(_FILE) and refuses to start
  without credentials; replaces set-password.sh
- Gitea Actions workflow builds and pushes
  registry.traberph.de/public/interval_viz (latest, sha-*, semver)
- Escape resets the chart zoom

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

html/app.js

@@ -1,6 +1,8 @@
 'use strict';
 
 const LANG_KEY = 'heatpump.lang';
+const DATASET_KEY = 'heatpump.dataset';
+const DATA_DIR = 'data/';
 const HOUR = 3600e3;
 
 const state = {
@@ -10,7 +12,9 @@ const state = {
   dataMin: 0,
   dataMax: 0,
   range: null,      // [from, to] in ms, or null = everything
-  source: '',
+  datasets: [],     // CSV file names in data/
+  source: '',       // name of the loaded dataset or local file
+  localFile: false, // source was opened via "Load CSV…"
   error: null,      // { key, params } so it can be re-rendered on language change
 };
 
@@ -42,6 +46,7 @@ function setLang(lang) {
     if (el.dataset.i18n === 'note') el.innerHTML = t('note');
     else el.textContent = t(el.dataset.i18n);
   });
+  $('dataset').setAttribute('aria-label', t('dataset'));
   document.querySelectorAll('[data-lang]').forEach(b => b.setAttribute('aria-pressed', String(b.dataset.lang === lang)));
   render();
 }
@@ -119,11 +124,11 @@ function parseCsv(text) {
   return { events, phases };
 }
 
-function load(text, source) {
+function load(text, source, localFile = false) {
   try {
     const { events, phases } = parseCsv(text);
     Object.assign(state, {
-      events, phases, source, error: null, range: null,
+      events, phases, source, localFile, error: null, range: null,
       dataMin: events[0].t, dataMax: events[events.length - 1].t,
     });
   } catch (err) {
@@ -157,12 +162,14 @@ const tilesHtml = tiles => tiles.map(([key, value, cls = '']) =>
   `<div class="tile"><div class="k">${escapeHtml(t(key))}</div><div class="v ${cls}">${escapeHtml(value)}</div></div>`).join('');
 
 function render() {
+  renderDatasetSelect();
   const src = $('source');
   if (state.error) {
     src.textContent = t(state.error.key, state.error.params);
     src.className = 'sub error';
   } else {
-    src.textContent = state.source || t('loading');
+    // with a dropdown the selected entry already names the source
+    src.textContent = $('dataset').hidden ? state.source || t('loading') : '';
     src.className = 'sub';
   }
   if (!state.events.length) return;
@@ -178,6 +185,17 @@ function render() {
   renderStats();
 }
 
+function renderDatasetSelect() {
+  const select = $('dataset');
+  select.hidden = state.datasets.length < 2;
+  if (select.hidden) return;
+  const option = (value, label, extra = '') =>
+    `<option value="${escapeHtml(value)}"${extra}>${escapeHtml(label)}</option>`;
+  select.innerHTML = state.datasets.map(name => option(name, name)).join('') +
+    (state.localFile ? option('', `${t('localFile')}: ${state.source}`, ' disabled') : '');
+  select.value = state.localFile ? '' : state.source;
+}
+
 function drawChart() {
   const accent = css('--accent'), ink = css('--ink'), ink2 = css('--ink-2'), line = css('--line');
 
@@ -283,20 +301,58 @@ document.querySelectorAll('[data-span]').forEach(btn => btn.addEventListener('cl
 $('file').addEventListener('change', async e => {
   const file = e.target.files[0];
   e.target.value = '';  // allow re-selecting the same file
-  if (file) load(await file.text(), file.name);
+  if (file) load(await file.text(), file.name, true);
+});
+
+// Escape resets the zoom, like a double-click in the chart
+document.addEventListener('keydown', e => {
+  if (e.key !== 'Escape' || e.defaultPrevented || !state.range) return;
+  if (e.target.closest('select, input')) return;  // let open controls handle their own Escape
+  setRange(null);
 });
 
 matchMedia('(prefers-color-scheme: dark)').addEventListener('change', render);
 
-setLang(detectLang());
+$('dataset').addEventListener('change', e => loadDataset(e.target.value));
 
-fetch('history.csv', { cache: 'no-cache' })
-  .then(r => {
+async function loadDataset(name) {
+  try {
+    const r = await fetch(DATA_DIR + encodeURIComponent(name), { cache: 'no-cache' });
     if (!r.ok) throw new Error(`HTTP ${r.status}`);
-    return r.text();
-  })
-  .then(text => load(text, 'history.csv'))
-  .catch(err => {
-    state.error = { key: 'errFetch', params: { status: err.message } };
+    load(await r.text(), name);
+    // remember only selections that actually loaded
+    if (!state.error) try { localStorage.setItem(DATASET_KEY, name); } catch { /* storage unavailable */ }
+  } catch (err) {
+    state.error = { key: 'errFetch', params: { file: name, status: err.message } };
     render();
-  });
+  }
+}
+
+// data/ is served as an nginx JSON directory listing: [{ name, type, mtime, size }, …]
+async function init() {
+  setLang(detectLang());
+  let files = [];
+  try {
+    const r = await fetch(DATA_DIR, { cache: 'no-cache' });
+    if (!r.ok) throw new Error(`HTTP ${r.status}`);
+    files = (await r.json())
+      .filter(f => f.type === 'file' && /\.csv$/i.test(f.name))
+      .sort((a, b) => a.name.localeCompare(b.name));
+  } catch (err) {
+    state.error = { key: 'errFetch', params: { file: DATA_DIR, status: err.message } };
+    return render();
+  }
+  if (!files.length) {
+    state.error = { key: 'errNoData' };
+    return render();
+  }
+  state.datasets = files.map(f => f.name);
+
+  // last selection if still present, otherwise the most recently modified file
+  let saved = null;
+  try { saved = localStorage.getItem(DATASET_KEY); } catch { /* storage unavailable */ }
+  const newest = files.reduce((a, b) => Date.parse(b.mtime) > Date.parse(a.mtime) ? b : a);
+  loadDataset(state.datasets.includes(saved) ? saved : newest.name);
+}
+
+init();