feat: add wallet profile database schema and repositories (#11)

- Add SQLAlchemy models for wallet profiles, funding transfers, and relationships
- Add WalletRepository, FundingRepository, RelationshipRepository with async support
- Add DatabaseManager for connection and session management
- Add Alembic migration for initial schema
- Include comprehensive test suite with 21 tests using in-memory SQLite

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

alembic/env.py

@@ -0,0 +1,71 @@
+"""Alembic migration environment configuration."""
+
+import os
+from logging.config import fileConfig
+
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+
+from polymarket_insider_tracker.storage.models import Base
+
+# this is the Alembic Config object
+config = context.config
+
+# Interpret the config file for Python logging
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# Target metadata for 'autogenerate' support
+target_metadata = Base.metadata
+
+# Get database URL from environment variable or config
+database_url = os.environ.get("SQLALCHEMY_DATABASE_URL")
+if database_url:
+    config.set_main_option("sqlalchemy.url", database_url)
+
+
+def run_migrations_offline() -> None:
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL and not an Engine,
+    though an Engine is acceptable here as well. By skipping the Engine
+    creation we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online() -> None:
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine and associate a
+    connection with the context.
+    """
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section, {}),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        context.configure(connection=connection, target_metadata=target_metadata)
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()