feat(live): board dynamique sans refresh (issue #15)

Diffusion SSE sur toutes les mutations (move, création, capture,
étiquettes) via _publish_board_changed; GET /api/board/{o}/{r}
(fragments _card.html rendus serveur, même pipeline que la page);
board-live.js: diff en place par colonne avec animation FLIP,
application différée pendant un drag, filtres/compteurs réappliqués,
repli par sondage 45 s sans webhooks. Carte extraite en partiel
_card.html partagé page/API.

static/js/board-live.js

@@ -0,0 +1,148 @@
+/**
+ * Kanbante — dynamic board (issue #15).
+ *
+ * The board reflects reality without a manual refresh: any change
+ * (another session, Gitea via webhook/labels, capture) is pushed
+ * over SSE; the client then fetches server-rendered card fragments
+ * from /api/board/<repo> and swaps only the columns that changed,
+ * animating surviving cards to their new place (FLIP). A discreet
+ * 45 s poll covers installs without Gitea webhooks. Local drags are
+ * never interrupted: a refresh arriving mid-drag waits for its end.
+ * Filters, scroll, the detail drawer and Sortable all survive,
+ * because only column contents are replaced — never the page.
+ */
+(function () {
+    var match = window.location.pathname.match(/^\/board\/(.+)$/);
+    if (!match) return;
+    var repoPath = match[1].replace(/\/$/, '');
+    var milestone = new URLSearchParams(window.location.search).get('milestone') || '';
+    var apiUrl = '/api/board/' + repoPath + (milestone ? '?milestone=' + encodeURIComponent(milestone) : '');
+    var repoFullName = repoPath.split('/').map(decodeURIComponent).join('/');
+
+    var lastEventAt = Date.now();
+    var inFlight = false;
+    var queued = false;
+    var debounce = null;
+    var failedOnce = false;
+
+    function signature(html) {
+        var h = 0;
+        for (var i = 0; i < html.length; i++) {
+            h = ((h << 5) - h + html.charCodeAt(i)) | 0;
+        }
+        return html.length + ':' + h;
+    }
+
+    function captureRects() {
+        var rects = {};
+        document.querySelectorAll('.kanban-card').forEach(function (card) {
+            rects[card.getAttribute('data-issue')] = card.getBoundingClientRect();
+        });
+        return rects;
+    }
+
+    function playFlip(before) {
+        if (window.matchMedia('(prefers-reduced-motion: reduce)').matches) return;
+        document.querySelectorAll('.kanban-card').forEach(function (card) {
+            var key = card.getAttribute('data-issue');
+            var old = before[key];
+            if (!old) {
+                card.animate(
+                    [{ opacity: 0, transform: 'scale(0.96)' }, { opacity: 1, transform: 'none' }],
+                    { duration: 220, easing: 'ease-out' }
+                );
+                return;
+            }
+            var now = card.getBoundingClientRect();
+            var dx = old.left - now.left;
+            var dy = old.top - now.top;
+            if (dx || dy) {
+                card.animate(
+                    [{ transform: 'translate(' + dx + 'px,' + dy + 'px)' }, { transform: 'none' }],
+                    { duration: 280, easing: 'ease-in-out' }
+                );
+            }
+        });
+    }
+
+    function showFallbackPill() {
+        if (document.getElementById('live-pill')) return;
+        var pill = document.createElement('button');
+        pill.id = 'live-pill';
+        pill.type = 'button';
+        pill.textContent = '🔄 Actualisation automatique en échec — cliquer pour recharger';
+        pill.addEventListener('click', function () { window.location.reload(); });
+        document.body.appendChild(pill);
+    }
+
+    function applyData(data) {
+        var before = captureRects();
+        var changed = false;
+        Object.keys(data.columns).forEach(function (col) {
+            var container = document.querySelector('.column-cards[data-column="' + col + '"]');
+            if (!container) return;
+            var payload = data.columns[col];
+            var sig = signature(payload.html);
+            if (container.getAttribute('data-sig') === sig) return;
+            container.innerHTML = payload.html;
+            container.setAttribute('data-sig', sig);
+            changed = true;
+        });
+        if (!changed) return;
+        playFlip(before);
+        if (window.kanbanteUpdateCounts) window.kanbanteUpdateCounts();
+        if (window.kanbanteRefreshHints) window.kanbanteRefreshHints();
+        if (window.kanbanteApplyFilters) window.kanbanteApplyFilters();
+    }
+
+    function refresh() {
+        if (window.__kanbanteDragging) {
+            setTimeout(refresh, 700);  // retry once the local drag ends
+            return;
+        }
+        if (inFlight) { queued = true; return; }
+        inFlight = true;
+        fetch(apiUrl, { headers: { 'Accept': 'application/json' } })
+            .then(function (r) { if (!r.ok) throw new Error('HTTP ' + r.status); return r.json(); })
+            .then(function (data) { failedOnce = false; applyData(data); })
+            .catch(function () { if (!failedOnce) { failedOnce = true; showFallbackPill(); } })
+            .finally(function () {
+                inFlight = false;
+                if (queued) { queued = false; refresh(); }
+            });
+    }
+
+    function scheduleRefresh() {
+        clearTimeout(debounce);
+        debounce = setTimeout(refresh, 400);
+    }
+
+    // 1. Push: SSE events about this repo (internal moves broadcast
+    //    {"type": "board-changed"}; webhooks broadcast their payload).
+    if (window.EventSource) {
+        var source = new EventSource('/api/stream');
+        source.addEventListener('gitea', function (e) {
+            try {
+                var payload = JSON.parse(e.data);
+                if (payload.repo && payload.repo !== repoFullName) return;
+            } catch (err) { /* unparseable -> refresh anyway */ }
+            lastEventAt = Date.now();
+            scheduleRefresh();
+        });
+        source.addEventListener('error', function () { /* EventSource retries itself */ });
+    }
+
+    // 2. Fallback poll (no webhooks configured, or SSE missed
+    //    something): only when visible and quiet for a full cycle.
+    setInterval(function () {
+        if (document.visibilityState === 'visible' && Date.now() - lastEventAt >= 45000) {
+            lastEventAt = Date.now();
+            refresh();
+        }
+    }, 5000);
+
+    // 3. Coming back to the tab: catch up immediately.
+    document.addEventListener('visibilitychange', function () {
+        if (document.visibilityState === 'visible') refresh();
+    });
+})();

static/js/board.js

@@ -152,6 +152,12 @@ document.addEventListener('DOMContentLoaded', () => {
         });
     }
 
+    // Exposed for board-live.js (issue #15): after a remote refresh
+    // swaps column fragments, filters/counts/hints must be recomputed.
+    window.kanbanteApplyFilters = applyFilters;
+    window.kanbanteRefreshHints = refreshEmptyHints;
+    window.kanbanteUpdateCounts = updateCounts;
+
     // Keyboard: "/" jumps to the filter box.
     document.addEventListener('keydown', (e) => {
         if (e.key === '/' && !/INPUT|TEXTAREA|SELECT/.test(document.activeElement?.tagName || '')) {