Retire the Dashboard tab; Processes is the front page

The app repeated itself. The module list, /api/prefs/dashboard, applyPrefs and the
per-user dashboard blob are gone. Widgets stays and now says plainly that it is for
dashboards outside Ham Lab.

This also closes a bug: applyPrefs set the sampling rate from intervalMs inside the
dashboard layout, and reset it to the default when that field was absent — so with
per-user layouts, one account saving a dashboard could reset the sampling rate for the
whole machine. The sampler now has one source.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

web/src/api.ts

@@ -90,7 +90,6 @@ export interface Series {
 // Dashboard layout. `order` lists module ids top-to-bottom; `hidden` are modules switched
 // off; `hiddenItems` are individual rows ("net:wlp1s0", "fs:/boot/efi", "disk:sda", "temp:chip/label").
 export interface HistoryWindow { seconds: number; points: number; stride_sec: number; min_seconds: number; max_seconds: number }
-export interface DashPrefs { order?: string[]; hidden?: string[]; hiddenItems?: string[]; intervalMs?: number; widgets?: { id: string; type: 'stat' | 'gauge' | 'bar' | 'spark' | 'list'; sensor: string; title?: string }[] }
 
 export interface ServiceUnit { name: string; description: string; load: string; active: string; sub: string; enabled: string; failed: boolean }
 export interface ServiceDetail extends ServiceUnit { props: Record<string, string> }
@@ -208,8 +207,6 @@ export const api = {
   serviceAction: (unit: string, action: string) => req<void>('POST', `/api/services/${encodeURIComponent(unit)}/${action}`),
   historyWindow: () => req<HistoryWindow>('GET', '/api/prefs/history', undefined, true),
   setHistoryWindow: (seconds: number) => req<HistoryWindow>('PUT', '/api/prefs/history', { seconds }, true),
-  dashPrefs: () => req<DashPrefs>('GET', '/api/prefs/dashboard'),
-  saveDashPrefs: (p: DashPrefs) => req<void>('PUT', '/api/prefs/dashboard', p),
   login: (username: string, password: string) => req<{ user: string }>('POST', '/api/login', { username, password }, true),
   users: () => req<User[]>('GET', '/api/users', undefined, true),
   addUser: (name: string, password: string) => req<{ name: string }>('POST', '/api/users', { name, password }, true),