feat(database): create all core tables with migrations

Add database migrations for mockupAWS v0.2.0:

- DB-003: scenario_logs table
  * Stores received log entries with SHA256 hash for deduplication
  * PII detection flags
  * Metrics: size_bytes, token_count, sqs_blocks
  * Indexes on scenario_id, received_at, message_hash, has_pii

- DB-004: scenario_metrics table
  * Time-series storage for metrics aggregation
  * Supports: sqs, lambda, bedrock, safety metric types
  * Flexible JSONB metadata field
  * BRIN index on timestamp for efficient queries

- DB-005: aws_pricing table
  * Stores AWS service pricing by region
  * Supports price history with effective_from/to dates
  * Active pricing flag for current rates
  * Index on service, region, tier combination

- DB-006: reports table
  * Generated report tracking
  * Supports PDF and CSV formats
  * File path and size tracking
  * Metadata JSONB for extensibility

All tables include:
- UUID primary keys with auto-generation
- Foreign key constraints with CASCADE delete
- Appropriate indexes for query performance
- Check constraints for data validation

Tasks: DB-003, DB-004, DB-005, DB-006 complete

alembic/versions/48f2231e7c12_create_aws_pricing_table.py

@@ -0,0 +1,78 @@
+"""create aws_pricing table
+
+Revision ID: 48f2231e7c12
+Revises: 5e247ed57b77
+Create Date: 2026-04-07 13:50:15.040833
+
+"""
+
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+
+# revision identifiers, used by Alembic.
+revision: str = "48f2231e7c12"
+down_revision: Union[str, Sequence[str], None] = "5e247ed57b77"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    op.create_table(
+        "aws_pricing",
+        sa.Column(
+            "id",
+            postgresql.UUID(as_uuid=True),
+            primary_key=True,
+            server_default=sa.text("uuid_generate_v4()"),
+        ),
+        sa.Column(
+            "service", sa.String(50), nullable=False
+        ),  # 'sqs', 'lambda', 'bedrock'
+        sa.Column("region", sa.String(50), nullable=False),
+        sa.Column("tier", sa.String(50), server_default="standard", nullable=False),
+        sa.Column("price_per_unit", sa.DECIMAL(15, 10), nullable=False),
+        sa.Column(
+            "unit", sa.String(20), nullable=False
+        ),  # 'per_million_requests', 'per_gb_second', 'per_1k_tokens'
+        sa.Column(
+            "effective_from",
+            sa.Date(),
+            server_default=sa.text("CURRENT_DATE"),
+            nullable=False,
+        ),
+        sa.Column("effective_to", sa.Date(), nullable=True),
+        sa.Column("is_active", sa.Boolean(), server_default="true", nullable=False),
+        sa.Column("source_url", sa.String(500), nullable=True),
+        sa.Column("description", sa.Text(), nullable=True),
+    )
+
+    # Add constraints
+    op.create_check_constraint(
+        "chk_price_positive", "aws_pricing", sa.column("price_per_unit") >= 0
+    )
+
+    # Add indexes
+    op.create_index("idx_pricing_service", "aws_pricing", ["service"])
+    op.create_index("idx_pricing_region", "aws_pricing", ["region"])
+    op.create_index(
+        "idx_pricing_active",
+        "aws_pricing",
+        ["service", "region", "tier"],
+        postgresql_where=sa.text("is_active = true"),
+    )
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # Drop indexes
+    op.drop_index("idx_pricing_active", table_name="aws_pricing")
+    op.drop_index("idx_pricing_region", table_name="aws_pricing")
+    op.drop_index("idx_pricing_service", table_name="aws_pricing")
+
+    # Drop table
+    op.drop_table("aws_pricing")