docs(01): create phase 1 authentication plans

Phase 1: Authentication & Account Basics
- 7 plans in 4 waves
- Covers AUTH-01 through AUTH-05 requirements
- Foundation for household features in Phase 2
- Ready for execution

.planning/phases/01-authentication/01-02-PLAN.md

@@ -0,0 +1,136 @@
+---
+phase: 01-authentication
+plan: 02
+type: execute
+wave: 1
+depends_on: []
+files_modified: ["lib/features/authentication/data/models/auth_user.dart", "lib/core/errors/auth_exceptions.dart", "lib/features/authentication/domain/repositories/auth_repository.dart"]
+autonomous: true
+user_setup: []
+
+must_haves:
+  truths:
+    - "Auth model represents user data consistently"
+    - "Auth exceptions provide clear error messages"
+    - "Auth repository defines interface for auth operations"
+  artifacts:
+    - path: "lib/features/authentication/data/models/auth_user.dart"
+      provides: "User data model"
+      min_lines: 15
+    - path: "lib/core/errors/auth_exceptions.dart"
+      provides: "Custom auth error handling"
+      min_lines: 20
+    - path: "lib/features/authentication/domain/repositories/auth_repository.dart"
+      provides: "Auth operations interface"
+      min_lines: 25
+  key_links:
+    - from: "lib/features/authentication/domain/repositories/auth_repository.dart"
+      to: "lib/features/authentication/data/models/auth_user.dart"
+      via: "method signatures"
+      pattern: "Future<AuthUser>|AuthUser"
+    - from: "lib/core/errors/auth_exceptions.dart"
+      to: "lib/features/authentication/domain/repositories/auth_repository.dart"
+      via: "exception handling"
+      pattern: "throws.*Exception"
+---
+
+<objective>
+Create authentication data models, error handling system, and repository interface.
+
+Purpose: Establish clean architecture foundations that separate concerns and provide type safety for authentication operations.
+Output: Domain models, custom exceptions, and repository interface that abstract Supabase implementation details.
+</objective>
+
+<execution_context>
+@~/.opencode/get-shit-done/workflows/execute-plan.md
+@~/.opencode/get-shit-done/templates/summary.md
+</execution_context>
+
+<context>
+@.planning/PROJECT.md
+@.planning/ROADMAP.md
+@.planning/STATE.md
+@.planning/phases/01-authentication/01-RESEARCH.md
+</context>
+
+<tasks>
+
+<task type="auto">
+  <name>Create AuthUser model</name>
+  <files>lib/features/authentication/data/models/auth_user.dart</files>
+  <action>
+    Create AuthUser data class that:
+    1. Extends or wraps Supabase User model for flexibility
+    2. Contains essential user fields (id, email, created_at, email_verified)
+    3. Includes fromSupabase() factory constructor
+    4. Includes copyWith() method for immutability
+    5. Includes toString() for debugging
+    6. Follows clean architecture pattern (data layer)
+    7. Has proper null safety handling
+  </action>
+  <verify>AuthUser model compiles without errors and properly handles Supabase User conversion</verify>
+  <done>AuthUser model provides clean abstraction over Supabase User with necessary fields</done>
+</task>
+
+<task type="auto">
+  <name>Create custom auth exceptions</name>
+  <files>lib/core/errors/auth_exceptions.dart</files>
+  <action>
+    Create custom exception classes that:
+    1. Extend Exception base class
+    2. Include specific auth error types:
+       - AuthException (base)
+       - InvalidCredentialsException
+       - UserNotFoundException
+       - WeakPasswordException
+       - EmailAlreadyInUseException
+       - NetworkException
+       - SessionExpiredException
+    3. Each exception has user-friendly message field
+    4. Include fromSupabaseError() factory for converting Supabase errors
+    5. Follow consistent error code patterns
+    6. Include proper documentation
+  </action>
+  <verify>Custom exceptions compile and provide meaningful error messages for different auth scenarios</verify>
+  <done>Comprehensive error handling system that maps Supabase errors to user-friendly messages</done>
+</task>
+
+<task type="auto">
+  <name>Create AuthRepository interface</name>
+  <files>lib/features/authentication/domain/repositories/auth_repository.dart</files>
+  <action>
+    Create abstract AuthRepository class that:
+    1. Defines interface for all auth operations:
+       - Future<AuthUser> signUp(String email, String password)
+       - Future<AuthUser> signIn(String email, String password)
+       - Future<void> signOut()
+       - Future<void> resetPassword(String email)
+       - Future<AuthUser?> getCurrentUser()
+       - Stream<AuthUser?> authStateChanges()
+    2. Returns custom exceptions for error cases
+    3. Follows clean architecture (domain layer)
+    4. Has comprehensive documentation
+    5. Uses proper async/await patterns
+    6. Includes null safety throughout
+  </action>
+  <verify>AuthRepository interface compiles without implementation and clearly defines all required auth methods</verify>
+  <done>Clean interface that abstracts authentication operations from Supabase implementation</done>
+</task>
+
+</tasks>
+
+<verification>
+1. All models and interfaces compile without errors
+2. Type safety is maintained throughout (no 'any' types)
+3. Error handling covers all major auth scenarios
+4. Clean architecture layers are properly separated
+5. Documentation is comprehensive for future implementers
+</verification>
+
+<success_criteria>
+Authentication domain foundation is established with proper models, error handling, and repository interface ready for implementation.
+</success_criteria>
+
+<output>
+After completion, create `.planning/phases/01-authentication/01-02-SUMMARY.md`
+</output>