Adds a Usage Monitor modal (Worker menu + wired to the footer/Mission-Control
usage pill's Open command): dynamic gauges built from UsageSnapshotDto.Limits
with gate-threshold marks, a stale/blocked-gate band, and Models/Tasks tabs
backed by GetModelUsageAsync/GetTaskUsageAsync over a 7d/30d/custom range.
Auto-seeding of monitor tiles was disabled in 724814f; Mission Control now
only shows ConPTY panes. Removes Monitors/EnsureMonitor/SeedActive, the
detach/re-dock machinery, MonitorPaneView and the detached monitor window,
plus their tests and orphaned localization keys.
TaskMonitorViewModel itself stays: DetailsIslandViewModel still uses it as
the backing state for the task Log/AgentState/AskUser-question UI, so only
its Mission-Control-only members (Title/DisplayTitle, detach, cancel command,
IMissionControlPane) were stripped. IMissionControlPane/Panes were kept
(now a 1:1 mirror of ConPtySessions) rather than dissolved, to avoid
churning the still-live ConPTY pane tests and AXAML for a single-implementer
interface.
Visual verification still open: Mission Control with several open ConPTY
tiles, and the Focus/Overview toggle.
Collapses the ~10 per-modal Show*Modal Func callbacks (wired separately on the shell and the lists island) into one IDialogService + WindowDialogService impl. Removes the RepoImport/WorktreesOverview dialog construction duplicated across MainWindow and ListsIslandView, plus the Confirm/Error dialogs duplicated in both code-behinds. Shell/lists Open* commands now route through an injected Dialogs handle (propagated shell->lists); the per-list worktrees overview also wires conflict resolution now, matching the global one. No VM ctor changes (Dialogs is a settable seam), so no test-fake impact.
mika kuns