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

src/ClaudeDo.Ui/CLAUDE.md

@@ -32,7 +32,7 @@ ViewModels/
 Views/          — mirrors the VM layout; Islands/Detail/ holds TaskHeaderBar,
                   DescriptionStepsCard, WorkConsole; plus SessionTerminalView
 Views/Controls/ — MarkdownView, ModalShell, ThemedDatePicker, DiffLinesView, InheritedBadge,
-                  AgentConfigEditor
+                  AgentConfigEditor, UsagePill, UsageGaugeBar
 Design/         — Tokens.axaml (design tokens; merged before styles)
                   + IslandStyles.axaml (component styles + the filled icon geometry library)
 ```
@@ -58,7 +58,7 @@ Design/         — Tokens.axaml (design tokens; merged before styles)
 | `ListSettingsModalViewModel` | Name, working dir, commit type, "manual list" flag, `VerifyCommand`, delete. Hosts the shared `AgentConfigEditorViewModel` as `Agent` (scope=List) — ⚠️ save delegates to `Agent.SaveAsync(verifyCommand)` because both land in the same `list_config` row via one `UpdateListConfig` call and would otherwise clobber each other. |
 | `WeeklyReportModalViewModel` | Range pickers default "since last standup weekday → today", cached per range. |
 | `MergeHelperSelectionModalViewModel` | "Let Claude handle it" picker → [conpty-sessions](../../docs/explore-notes/conpty-sessions.md). |
-| `UsageMonitorModalViewModel` | Opened from the usage pill; gauges are **dynamic** per `UsageSnapshotDto.Limits` row. |
+| `UsageMonitorModalViewModel` | Opened from the usage pill (shown **before** the data loads via `BeginLoad`); gauges are **dynamic** per `UsageSnapshotDto.Limits` row, and the 5h/7d ones carry three draggable stage markers (soft/hard/gate) via `UsageGaugeBar` + the pure `UsageThresholdDrag`, plus a colour-matched legend with a `NumericUpDown` per stage → [usage-monitoring](../../docs/explore-notes/usage-monitoring.md). |
 
 Self-explanatory: `RepoImportModalViewModel` (bulk-create lists from git repos; already-wired
 repos disabled), `MergeModalViewModel`, `WorktreesOverviewModalViewModel`,