feat(routing): add conditional routing rules for document-to-pipeline assignment

- Add PipelineRoutingRule model to app/models.py
- Add Alembic migration 027_add_routing_rules
- Add routing engine (app/utils/routing_engine.py) with rule evaluation
- Add CRUD API endpoints (app/api/routing_rules.py)
- Register router in app/api/__init__.py
- Add comprehensive tests (73 tests, all passing)

Supported fields: file_type, document_type, category, filename, size, metadata.*
Supported operators: equals, not_equals, contains, not_contains, regex, gt, lt, gte, lte
First-match-wins evaluation with default pipeline fallback

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

migrations/versions/027_add_routing_rules.py

@@ -0,0 +1,46 @@
+"""Add pipeline_routing_rules table for conditional document routing.
+
+Revision ID: 027_add_routing_rules
+Revises: 026_add_scheduled_jobs
+Create Date: 2026-03-09
+"""
+
+from typing import Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "027_add_routing_rules"
+down_revision: Union[str, None] = "026_add_scheduled_jobs"
+depends_on: Union[str, None] = None
+
+
+def upgrade() -> None:
+    """Create pipeline_routing_rules table."""
+    op.create_table(
+        "pipeline_routing_rules",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("owner_id", sa.String(), nullable=True),
+        sa.Column("name", sa.String(255), nullable=False),
+        sa.Column("position", sa.Integer(), nullable=False, server_default="0"),
+        sa.Column("field", sa.String(255), nullable=False),
+        sa.Column("operator", sa.String(50), nullable=False),
+        sa.Column("value", sa.String(1024), nullable=False),
+        sa.Column("target_pipeline_id", sa.Integer(), nullable=False),
+        sa.Column("is_active", sa.Boolean(), nullable=False, server_default="1"),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+        sa.PrimaryKeyConstraint("id"),
+        sa.ForeignKeyConstraint(["target_pipeline_id"], ["pipelines.id"]),
+    )
+    op.create_index("ix_routing_rules_id", "pipeline_routing_rules", ["id"])
+    op.create_index("ix_routing_rules_owner_id", "pipeline_routing_rules", ["owner_id"])
+    op.create_index("ix_routing_rules_target_pipeline_id", "pipeline_routing_rules", ["target_pipeline_id"])
+
+
+def downgrade() -> None:
+    """Drop pipeline_routing_rules table."""
+    op.drop_index("ix_routing_rules_target_pipeline_id", "pipeline_routing_rules")
+    op.drop_index("ix_routing_rules_owner_id", "pipeline_routing_rules")
+    op.drop_index("ix_routing_rules_id", "pipeline_routing_rules")
+    op.drop_table("pipeline_routing_rules")