feat(01-03): export all public APIs from package root

- Export error types (KBError, NetworkError, ValidationError, SystemError, AuthError, ErrorType)
- Export config (KBSettings, get_settings)
- Export retry (retry_on_network_error)
- Clean import interface for users

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

.planning/ROADMAP.md

@@ -93,12 +93,12 @@ Phases execute in numeric order: 1 → 2 → 3 → 4
 
 | Phase | Plans Complete | Status | Completed |
 |-------|----------------|--------|-----------|
-| 1. Foundation | 0/3 | Ready to execute | - |
+| 1. Foundation | 2/3 | In Progress | 01-02, 01-01 |
 | 2. Platform Skills | 0/3 | Not started | - |
 | 3. Processing Skills | 0/2 | Not started | - |
 | 4. Analysis & Orchestration | 0/3 | Not started | - |
 
 ---
 *Roadmap created: 2026-03-13*
-*Last updated: 2026-03-13 - Phase 1 plans created*
+*Last updated: 2026-03-13 - Phase 1 in progress (2/3 plans complete)*
 *Granularity: coarse (4 phases)*

kb_pipeline/__init__.py

@@ -13,8 +13,19 @@ from .schemas import (
     StepDefinition,
 )
 from .state import WorkflowStateManager
+from .errors import (
+    KBError,
+    NetworkError,
+    ValidationError,
+    SystemError,
+    AuthError,
+    ErrorType,
+)
+from .config import KBSettings, get_settings
+from .retry import retry_on_network_error
 
 __all__ = [
+    # Schemas
     "StepInput",
     "StepOutput",
     "StepResult",
@@ -22,7 +33,20 @@ __all__ = [
     "StepRecord",
     "WorkflowState",
     "StepDefinition",
+    # State
     "WorkflowStateManager",
+    # Errors
+    "KBError",
+    "NetworkError",
+    "ValidationError",
+    "SystemError",
+    "AuthError",
+    "ErrorType",
+    # Config
+    "KBSettings",
+    "get_settings",
+    # Retry
+    "retry_on_network_error",
 ]
 
 __version__ = "0.1.0"