feat(04-04): add PipelineInput/Output/Config schemas

- PipelineInput: url (required), output_dir, skip_completed
- PipelineOutput: success, error_message, results, content_dir
- PipelineConfig: steps, output_dir, skip_completed, max_retries

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

kb_pipeline/schemas.py

@@ -9,6 +9,7 @@ from pydantic import BaseModel, Field
 from typing import Optional, Dict, Literal, Any, List
 from datetime import datetime
 from enum import Enum
+from pathlib import Path
 
 
 class StepStatus(str, Enum):
@@ -353,3 +354,54 @@ class AnalyzeOutput(StepOutput):
     key_insights: List[str] = Field(default_factory=list, description="Key insights")
     tags: List[str] = Field(default_factory=list, description="Recommended tags")
     stats: Dict[str, Any] = Field(default_factory=dict, description="Statistics about analysis")
+
+
+# =============================================================================
+# Pipeline Schemas (Phase 04-04)
+# =============================================================================
+
+
+class PipelineInput(BaseModel):
+    """Pipeline input - URL to process
+
+    Attributes:
+        url: URL to process (required)
+        output_dir: Optional output directory for content
+        skip_completed: Skip already completed steps (default True)
+    """
+    url: str = Field(..., min_length=1, description="URL to process")
+    output_dir: Optional[Path] = Field(None, description="Output directory for content")
+    skip_completed: bool = Field(default=True, description="Skip already completed steps")
+
+
+class PipelineOutput(BaseModel):
+    """Pipeline output - results from all steps
+
+    Attributes:
+        success: Whether the pipeline completed successfully
+        error_message: Error message if pipeline failed
+        results: Dictionary of results from each step
+        content_dir: Path to the content directory
+    """
+    success: bool = Field(..., description="Whether the pipeline completed successfully")
+    error_message: Optional[str] = Field(None, description="Error message if pipeline failed")
+    results: Dict[str, Any] = Field(default_factory=dict, description="Results from each step")
+    content_dir: Optional[Path] = Field(None, description="Path to the content directory")
+
+
+class PipelineConfig(BaseModel):
+    """Pipeline configuration
+
+    Attributes:
+        steps: Steps to execute in order (default: parse, download, asr, analyze)
+        output_dir: Base output directory
+        skip_completed: Skip completed steps (default True)
+        max_retries: Max retries per step (default 3)
+    """
+    steps: List[str] = Field(
+        default_factory=lambda: ["parse", "download", "asr", "analyze"],
+        description="Steps to execute in order"
+    )
+    output_dir: Optional[Path] = Field(None, description="Base output directory")
+    skip_completed: bool = Field(default=True, description="Skip completed steps")
+    max_retries: int = Field(default=3, description="Max retries per step")