Refactor database initialization and migrations to SQLAlchemy

[edgeinfinity1]

Motivation

• Replace legacy raw SQL / custom pool helpers with SQLAlchemy async engines and metadata so initial setup and migrations work with the new ORM layer.
• Normalize MySQL vs SQLite differences using SQLAlchemy execution/inspection instead of ad-hoc string queries.
• Align ORM model column types and constraints to match the intended schema used by the migrations and initializer.

Description

• Rewrote maica/initializer/init_db.py to create MySQL databases via a server-level async engine and to create tables using SqlBaseAuth.metadata.create_all and SqlBaseData.metadata.create_all through SQLAlchemy async engines instead of ConnUtils raw queries.
• Converted migrations migration_1.py..migration_4.py to use DatabaseUtils.engine_data / DatabaseUtils.engine_auth with text() execution and SQLAlchemy inspection, removing ConnUtils query_modify calls and handling MySQL/SQLite syntax differences appropriately.
• In migration_2.py the mv_meta table is created via the ORM table metadata (SqlMvMeta.__table__.create(checkfirst=True)) and MySQL-only ALTERs are executed with text() when needed.
• In migration_3.py the presence of suspended_until is detected with SQLAlchemy inspect and the column is added with an ALTER TABLE executed via the SQLAlchemy connection when missing.
• In migration_4.py added helper async def _create_index_if_missing using SQLAlchemy inspect(...).get_indexes to avoid duplicate index creation, and applied table ALTERs / index creation through the async engine, preserving MySQL vs SQLite differences.
• Updated ORM definitions in maica/maica_utils/database_models.py to declare explicit types and constraints (String, Text, Boolean, DateTime), add __table_args__ unique constraint for ms_cache.hash, and otherwise match the adjusted initializer/migration expectations.
• Removed direct use of legacy pool objects from the modified files and replaced them with SQLAlchemy engine/session based operations.

Testing

• Ran a syntax/bytecode check with python -m compileall maica/initializer/init_db.py maica/initializer/migrations/migration_1.py maica/initializer/migrations/migration_2.py maica/initializer/migrations/migration_3.py maica/initializer/migrations/migration_4.py maica/maica_utils/database_models.py, which completed successfully.

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Codex Task