feat: UI polish, lint fixes, onboarding redesign, help page expansion, and test improvements

Broad update across dashboard pages, components, extensions, and lib code. Includes ESLint config additions, onboarding flow redesign, settings page refactor, help page content expansion, dead code removal, and test mock fixes. Adds dev docs and public assets.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/extensions/__tests__/ai-consent.test.ts

@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
 import { describe, it, expect, vi, beforeEach } from 'vitest'
 import { createMockSupabase } from '@/tests/helpers'
 import {

lib/extensions/__tests__/sectors.test.ts

@@ -1,4 +1,4 @@
-import { resolve, join, dirname } from 'path'
+import { resolve, join } from 'path'
 import { readdirSync, readFileSync } from 'fs'
 
 /**
@@ -74,6 +74,7 @@ describe('sectors registry', () => {
   })
 
   it('getSector returns undefined for unknown slug', () => {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
     const sector = getSector('invalid' as any)
     expect(sector).toBeUndefined()
   })