feat: add Dashboard tab with live GPU overview

Add a new Dashboard tab as the default/first tab (Dashboard - Curve -
Performance - Fans) showing a full GPU overview.

Backend:
- New hal/dashboard.py: one-shot static GPU info via NVML (VBIOS, CUDA
  cores, compute capability, bus width, BAR1/CPU-accessible VRAM,
  Resizable BAR, PCIe max, max clocks, power limits, temp thresholds,
  persistence mode, fan count, serial, board part number, UUID).
  ROP count and VRAM type are best-effort from a per-model table since
  NVML does not expose them.
- New /api/dashboard endpoint.
- MonitoringSample gains live throttle_reasons (+label), PCIe link
  width/generation (downclocks when idle, so read per poll), and VRAM
  temp (from the MEMORY thermal sensor, if exposed).

Frontend:
- New Dashboard component: critical top row (throttling, voltage,
  GPU/VRAM temps), full live-monitor grid with sparklines, and a static
  GPU-information grid. Unavailable fields are omitted.
- useDashboard hook + DashboardInfo type + api.client dashboard().

Also: restrict CORS to localhost origins (end-anchored), make
_int_key_deltas fail closed on bad keys, and clean up lint blockers in
server.py/monitoring.py.

frontend/src/types.ts

@@ -8,7 +8,7 @@ export interface VFPoint {
   delta_mhz: number;
   effective_freq_khz: number;
   effective_freq_mhz: number;
-  domain: 'gpu' | 'memory';
+  domain: "gpu" | "memory";
 }
 
 export interface CurveState {
@@ -34,6 +34,46 @@ export interface MonitoringSample {
   gpu_util_pct: number | null;
   mem_util_pct: number | null;
   mem_clock_mhz: number | null;
+  throttle_reasons: number | null;
+  throttle_reasons_label: string | null;
+  pcie_link_width: number | null;
+  pcie_link_generation: number | null;
+  mem_temp_c: number | null;
+}
+
+export interface DashboardInfo {
+  name: string | null;
+  index: number;
+  driver_version: string | null;
+  vbios_version: string | null;
+  serial: string | null;
+  board_part_number: string | null;
+  uuid: string | null;
+  cuda_cores: number | null;
+  cuda_compute_capability: string | null;
+  rop_count: number | null;
+  vram_total_bytes: number | null;
+  vram_type: string | null;
+  memory_bus_width: number | null;
+  bar1_total_bytes: number | null;
+  bar1_used_bytes: number | null;
+  resizable_bar: boolean | null;
+  pcie_link_width: number | null;
+  pcie_link_generation: number | null;
+  pcie_max_link_width: number | null;
+  pcie_max_link_generation: number | null;
+  max_graphics_clock_mhz: number | null;
+  max_memory_clock_mhz: number | null;
+  max_video_clock_mhz: number | null;
+  power_limit_w: number | null;
+  power_min_limit_w: number | null;
+  power_max_limit_w: number | null;
+  persistence_mode: boolean | null;
+  num_fans: number | null;
+  supported_throttle_reasons: number | null;
+  temp_slowdown_c: number | null;
+  temp_shutdown_c: number | null;
+  temp_gpu_max_c: number | null;
 }
 
 export interface GpuInfo {
@@ -73,7 +113,7 @@ export interface FanPoint {
 
 export interface FanState {
   fan_pct: number | null;
-  fan_mode: 'auto' | 'curve' | null;
+  fan_mode: "auto" | "curve" | null;
   min_fan_pct: number | null;
   max_fan_pct: number | null;
   curve: FanPoint[] | null;