feat: per-task image/annotations, annotation editor toolbar, Tailwind compiled

- Add per-task file upload with image preview in task editor
- Add dedicated annotation editor page (task_drawing.html) with Fabric.js
- Add color picker, stroke width, and line dash controls to annotation toolbar
- Apply property changes to selected objects in real-time
- Disable style controls until a drawing tool or object is selected
- Remove zoom/pan from annotation toolbar (simplified UX)
- Auto-switch to select mode after placing annotation elements
- Show annotation overlay on task image previews (read-only canvas)
- Add file proxy route in measure blueprint for task file access
- Add file_path/file_type fields to TaskCreate/TaskUpdate Pydantic schemas
- Replace Tailwind CDN with compiled CSS (tailwind.config.js with full shades)
- Fix Alpine.js x-init crash: extract annotations JSON to <script> tags
  (recipe_preview.html, task_execute.html) to avoid HTML attribute breakage

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

client/tailwind.config.js

@@ -12,11 +12,31 @@ module.exports = {
           DEFAULT: '#2563EB',
           dark: '#1E40AF',
           light: '#3B82F6',
+          50: '#EFF6FF',
+          100: '#DBEAFE',
+          200: '#BFDBFE',
+          300: '#93C5FD',
+          400: '#60A5FA',
+          500: '#3B82F6',
+          600: '#2563EB',
+          700: '#1D4ED8',
+          800: '#1E40AF',
+          900: '#1E3A8A',
         },
         steel: {
           DEFAULT: '#64748B',
           light: '#94A3B8',
           dark: '#475569',
+          50: '#F8FAFC',
+          100: '#F1F5F9',
+          200: '#E2E8F0',
+          300: '#CBD5E1',
+          400: '#94A3B8',
+          500: '#64748B',
+          600: '#475569',
+          700: '#334155',
+          800: '#1E293B',
+          900: '#0F172A',
         },
         measure: {
           pass: '#059669',