feat: Add Step Library API foundation (Phase 1: B.1-B.3, B.7)

Implements foundational types and API clients for Step Library:

Task B.3 - TypeScript Types:
- Created types/step.ts with comprehensive interfaces
- Step, StepListItem, StepCategory types
- StepContent with instructions, help_text, commands
- StepListParams for filtering/sorting
- Rating and Review types
- StepCreate/StepUpdate DTOs

Task B.1 - Steps API Client:
- Created api/steps.ts following existing patterns
- CRUD operations (list, get, create, update, delete)
- Search endpoint with query
- Popular tags endpoint
- Rating/review operations (rate, updateRating, deleteRating, getReviews)

Task B.2 - Step Categories API Client:
- Created api/stepCategories.ts
- List and get operations for categories

Task B.7 - Update API Index:
- Exported stepsApi and stepCategoriesApi
- Available for import from '@/api'

Phase 1 foundation complete. Ready for Phase 2 (UI components).
Build tested successfully.

Related: Issue #10

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

frontend/src/types/step.ts

@@ -0,0 +1,124 @@
+// Step Library Types
+
+export interface StepCommand {
+  label: string
+  command: string
+  command_type?: string
+}
+
+export interface StepContent {
+  instructions: string
+  help_text?: string
+  commands?: StepCommand[]
+}
+
+export interface Step {
+  id: string
+  title: string
+  step_type: 'decision' | 'action' | 'solution'
+  content: StepContent
+  visibility: 'private' | 'team' | 'public'
+  category_id?: string
+  category_name?: string
+  tags: string[]
+  usage_count: number
+  rating_average: number
+  rating_count: number
+  helpful_yes: number
+  helpful_no: number
+  is_featured: boolean
+  is_verified: boolean
+  created_by: string
+  author_name?: string
+  created_at: string
+  updated_at: string
+}
+
+export interface StepListItem {
+  id: string
+  title: string
+  step_type: string
+  visibility: string
+  category_id?: string
+  category_name?: string
+  tags: string[]
+  usage_count: number
+  rating_average: number
+  rating_count: number
+  is_featured: boolean
+  created_by: string
+  author_name?: string
+  created_at: string
+}
+
+export interface StepCategory {
+  id: string
+  name: string
+  description?: string
+  display_order: number
+  team_id?: string
+  is_active: boolean
+}
+
+export interface StepListParams {
+  visibility?: 'private' | 'team' | 'public'
+  category_id?: string
+  tags?: string[]
+  min_rating?: number
+  step_type?: 'decision' | 'action' | 'solution'
+  sort_by?: 'recent' | 'popular' | 'highest_rated' | 'most_used'
+  limit?: number
+  offset?: number
+}
+
+export interface PopularTag {
+  tag: string
+  count: number
+}
+
+export interface StepCreate {
+  title: string
+  step_type: 'decision' | 'action' | 'solution'
+  content: StepContent
+  visibility: 'private' | 'team' | 'public'
+  category_id?: string
+  tags?: string[]
+}
+
+export interface StepUpdate {
+  title?: string
+  step_type?: 'decision' | 'action' | 'solution'
+  content?: StepContent
+  visibility?: 'private' | 'team' | 'public'
+  category_id?: string
+  tags?: string[]
+}
+
+export interface RatingCreate {
+  rating: number
+  review_text?: string
+  verified_use: boolean
+}
+
+export interface RatingUpdate {
+  rating?: number
+  review_text?: string
+}
+
+export interface Rating {
+  id: string
+  step_id: string
+  user_id: string
+  rating: number
+  review_text?: string
+  verified_use: boolean
+  helpful_yes: number
+  helpful_no: number
+  created_at: string
+  updated_at: string
+  user_name?: string
+}
+
+export interface Review extends Rating {
+  // Same as Rating, just an alias for clarity
+}