feat(routing): linked complexity-boundary sliders — your own low/medium/high

The tier boundaries lived on the router and were global for every customer
of a hosted router; per-gateway tuning meant hand-editing score ranges. The
Routing page now has one track with two draggable handles (the low|medium
and medium|high boundaries) over three colored zones: handles push each
other (low can't cross medium — it shoves it along, and vice versa), the
numbers ride on the handles and the legend updates live, so nobody types
ranges by hand. Unchecked = the router's own bands, untouched behavior.

Under the hood the gateway re-maps the router's CONTINUOUS complexity score
with the user's boundaries ([routing.bands] low/medium in gateway.toml,
validated 0 < low < medium < 1) before tier chains, escalation and stats —
verified live: with bands at 0.70/0.72 a score-0.27 request that used to be
medium routed low, and back after restoring the defaults.

2 new strings in all 7 languages.

web/js/i18n/de.js

@@ -629,4 +629,6 @@ export default {
   "routing.tasks.tierHint": "Welches Modell diese Aufgabe bei welcher Komplexität bedient; \"jede\" führt auf allen Stufen. Reihenfolge = Fallback-Reihenfolge. High eskaliert weiterhin über \"jede\"-Einträge.",
   "routing.tasks.tierAny": "jede Komplexität",
   "routing.tasks.addModel": "Modell",
+  "routing.bands.enable": "Eigene Komplexitätsgrenzen",
+  "routing.bands.hint": "Ziehen Sie die Griffe: wo low endet und high beginnt — die Griffe schieben einander, die Zahlen aktualisieren sich live. Der kontinuierliche Router-Score wird mit IHREN Grenzen neu eingeteilt; ohne Häkchen gelten die Grenzen des Routers.",
 };

web/js/i18n/en.js

@@ -622,4 +622,6 @@ export default {
   "routing.tasks.tierHint": "Which model serves this task at which complexity; \"any\" leads at every tier. Order = fallback order. High verdicts still escalate over any-tier pins.",
   "routing.tasks.tierAny": "any complexity",
   "routing.tasks.addModel": "model",
+  "routing.bands.enable": "My complexity boundaries",
+  "routing.bands.hint": "Drag the handles to set where low ends and where high begins — the handles push each other, the numbers update live. The router's continuous score is re-mapped with YOUR boundaries; unchecked = the router's own bands.",
 };

web/js/i18n/es.js

@@ -629,4 +629,6 @@ export default {
   "routing.tasks.tierHint": "Qué modelo atiende esta tarea en qué complejidad; «cualquiera» lidera en todos los niveles. El orden = orden de respaldo. Un veredicto high sigue escalando sobre las entradas «cualquiera».",
   "routing.tasks.tierAny": "cualquier complejidad",
   "routing.tasks.addModel": "modelo",
+  "routing.bands.enable": "Mis límites de complejidad",
+  "routing.bands.hint": "Arrastra los tiradores: dónde termina low y dónde empieza high — se empujan entre sí y las cifras se actualizan en vivo. La puntuación continua del router se re-mapea con TUS límites; sin marcar = las bandas del propio router.",
 };

web/js/i18n/fr.js

@@ -629,4 +629,6 @@ export default {
   "routing.tasks.tierHint": "Quel modèle sert cette tâche à quelle complexité ; « toute » mène à tous les niveaux. L'ordre = ordre de repli. Un verdict high escalade toujours au-dessus des entrées « toute ».",
   "routing.tasks.tierAny": "toute complexité",
   "routing.tasks.addModel": "modèle",
+  "routing.bands.enable": "Mes limites de complexité",
+  "routing.bands.hint": "Faites glisser les poignées : où finit low et où commence high — elles se poussent l'une l'autre, les chiffres se mettent à jour en direct. Le score continu du routeur est re-découpé avec VOS limites ; décoché = les bandes du routeur.",
 };

web/js/i18n/ru.js

@@ -621,4 +621,6 @@ export default {
   "routing.tasks.tierHint": "Какая модель обслуживает задачу на какой сложности; «любая» ведёт на всех уровнях. Порядок = порядок фолбэка. Вердикт high по-прежнему эскалирует поверх «любых».",
   "routing.tasks.tierAny": "любая сложность",
   "routing.tasks.addModel": "модель",
+  "routing.bands.enable": "Мои границы сложности",
+  "routing.bands.hint": "Тяните ручки: где кончается low и где начинается high — ручки толкают друг друга, цифры обновляются на лету. Непрерывный score роутера пересчитывается ВАШИМИ границами; галочка снята — действуют пороги самого роутера.",
 };

web/js/i18n/tr.js

@@ -629,4 +629,6 @@ export default {
   "routing.tasks.tierHint": "Bu görevi hangi karmaşıklıkta hangi model karşılar; \"her\" tüm katmanlarda önde gider. Sıra = yedekleme sırası. High kararı \"her\" girdilerinin üzerine yine tırmanır.",
   "routing.tasks.tierAny": "her karmaşıklık",
   "routing.tasks.addModel": "model",
+  "routing.bands.enable": "Kendi karmaşıklık sınırlarım",
+  "routing.bands.hint": "Tutamaçları sürükleyin: low nerede biter, high nerede başlar — tutamaçlar birbirini iter, sayılar anlık güncellenir. Yönlendiricinin sürekli puanı SİZİN sınırlarınızla yeniden bölümlenir; işaret kaldırılırsa yönlendiricinin kendi bantları geçerli.",
 };

web/js/i18n/zh.js

@@ -629,4 +629,6 @@ export default {
   "routing.tasks.tierHint": "哪个模型在哪个复杂度上处理该任务；「任意」在所有层级领先。顺序即回退顺序。high 判定仍会越过「任意」条目升级。",
   "routing.tasks.tierAny": "任意复杂度",
   "routing.tasks.addModel": "模型",
+  "routing.bands.enable": "自定义复杂度边界",
+  "routing.bands.hint": "拖动手柄设定 low 到哪里结束、high 从哪里开始 — 手柄会相互推动，数字实时更新。路由器的连续得分将按你的边界重新划分；取消勾选则使用路由器自身的边界。",
 };