feat(health): santé du flux — goulots et cartes zombies (issue #9)

app/flow.py: séjours par colonne reconstruits du journal,
médianes, colonne la plus lente; zombies = aucune activité
(journal/Gitea) depuis KANBANTE_ZOMBIE_DAYS (30). Pages /health
et /health/{o}/{r} + actions rapides (commenter/backlog/fermer).

static/js/health.js

@@ -0,0 +1,45 @@
+/**
+ * Kanbante — Flow health (issue #9): quick actions on zombie cards.
+ * Close/backlog reuse /api/move; the nudge reuses the comments API.
+ */
+(function () {
+    var csrf = (document.querySelector('meta[name="csrf-token"]') || {}).content || '';
+
+    function post(url, fields) {
+        var data = new FormData();
+        Object.keys(fields).forEach(function (k) { data.append(k, fields[k]); });
+        data.append('csrf_token', csrf);
+        return fetch(url, { method: 'POST', body: data }).then(function (r) {
+            return r.json().catch(function () { return {}; }).then(function (body) {
+                if (!r.ok || body.ok === false) throw new Error(body.error || ('HTTP ' + r.status));
+                return body;
+            });
+        });
+    }
+
+    document.addEventListener('click', function (e) {
+        var btn = e.target.closest('[data-zombie]');
+        if (!btn) return;
+        var repo = btn.getAttribute('data-repo');
+        var number = btn.getAttribute('data-number');
+        var column = btn.getAttribute('data-column');
+        var action = btn.getAttribute('data-zombie');
+        var parts = repo.split('/');
+        btn.disabled = true;
+        var done = function () { location.reload(); };
+        var fail = function (err) { btn.disabled = false; alert(err.message); };
+        if (action === 'comment') {
+            post('/api/issues/' + parts[0] + '/' + parts[1] + '/' + number + '/comments', {
+                body: '🧟 Cette carte est inactive depuis un moment — toujours pertinent ?'
+            }).then(done).catch(fail);
+        } else {
+            post('/api/move', {
+                repo_full_name: repo,
+                issue_number: number,
+                from_column: column,
+                to_column: action === 'close' ? 'done' : 'backlog',
+                to_order: number
+            }).then(done).catch(fail);
+        }
+    });
+})();

static/js/palette.js

@@ -17,6 +17,7 @@
         { icon: '🔮', label: 'Prévisions — on finit quand ?', href: '/forecast' },
         { icon: '🗣️', label: 'Standup automatique — hier, aujourd\'hui, blocages', href: '/standup' },
         { icon: '⚙️', label: 'Règles d\'automatisation', href: '/rules' },
+        { icon: '🩺', label: 'Santé du flux — goulots et zombies', href: '/health' },
         { icon: '👤', label: 'Mes issues', href: '/my' },
         { icon: '📰', label: 'Activité — journal des événements', href: '/activity' },
         { icon: '📊', label: 'Briefing quotidien', href: '/briefing' },