feat(usage): split throttle thresholds per bucket, add draggable gauge markers

src/ClaudeDo.Localization/locales/en.json

@@ -433,6 +433,10 @@
       "gateBlockedFormat": "Queue paused — {0}",
       "throttleFormat": "Queue throttled: {0}/{1} slots ({2})",
       "resetIn": "Reset in {0}",
+      "dragHint": "Drag a marker, or type the value below.",
+      "legendSoft": "Soft · 2 slots",
+      "legendHard": "Hard · 1 slot",
+      "legendGate": "Gate · pause",
       "gaugeSession": "Session (5h)",
       "gaugeWeeklyAll": "Week (all models)",
       "gaugeWeeklyScopedFormat": "Week ({0})",
@@ -657,7 +661,8 @@
     "weeklyReport": { "invalidRange": "Invalid date range.", "generating": "Generating report…", "error": "Error: {0}" },
     "usageMonitor": {
       "loadFailed": "Couldn't load usage data: {0}",
-      "refreshFailed": "Couldn't refresh usage: {0}"
+      "refreshFailed": "Couldn't refresh usage: {0}",
+      "thresholdSaveFailed": "Couldn't save the threshold: {0}"
     },
     "filesTab": { "workerOffline": "Worker offline.", "noneBundled": "No default agents bundled.", "allPresent": "All default agents already present.", "restored": "Restored {0} default agent(s).", "restoreFailed": "Restore failed: {0}", "resetToDefault": "Reset to the bundled default." },
     "sessionSkillsTab": { "installed": "Installed: {0}", "installFailed": "Install failed: {0}", "updated": "Updated.", "updateFailed": "Update failed: {0}", "removed": "Removed.", "removeFailed": "Remove failed: {0}" },