Chore!: Remove old migration scripts up to and including v0060

[izeigerman]

This reduces the number of DDL statements during state initialization and also helps reduce our technical debt.

[Copilot]

Pull Request Overview

This PR removes old migration scripts up to and including v0060 to reduce DDL statements during state initialization and technical debt. The key changes include:

• Removal of 61 migration scripts (v0001-v0060)
• Updated migration system to use v0060 as the minimum supported schema version
• Modified tooling and tests to account for the removal of old migrations

Reviewed Changes

Copilot reviewed 75 out of 75 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tooling/validating_migration_numbers.sh	Added condition to skip migration numbers less than or equal to 0
tests/fixtures/migrations/versions.json	Added new test fixture file with schema version 60
tests/fixtures/migrations/snapshots.json	Updated test fixture with migrated snapshot data
tests/fixtures/migrations/intervals.json	Added new test fixture for intervals data
tests/fixtures/migrations/environments.json	Updated environment fixture with migrated data
tests/core/test_integration.py	Removed references to obsolete _plan_dags table
tests/core/state_sync/test_state_sync.py	Updated migration tests and added test for old state version error
tests/core/state_sync/test_export_import.py	Removed default_catalog parameter from migrate calls
sqlmesh/utils/errors.py	Added new StateMigrationError exception
sqlmesh/migrations/v0096_remove_plan_dags_table.py	Added new migration to remove obsolete plan_dags table
sqlmesh/migrations/v0061_mysql_fix_blob_text_type.py	Removed references to plan_dags table
sqlmesh/migrations/v0060_move_audits_to_model.py	Removed entire migration file
sqlmesh/migrations/v0059_add_physical_version.py	Removed entire migration file
57 other migration files	Removed migration files v0001-v0058
sqlmesh/migrations/v0000_baseline.py	Transformed from backup/restore script to baseline initialization script
sqlmesh/core/state_sync/db/migrator.py	Updated migration system to support minimum schema version and handle old state errors
sqlmesh/core/state_sync/db/facade.py	Removed plan_dags table references
sqlmesh/core/state_sync/base.py	Added minimum schema version constants and updated migration indexing
sqlmesh/core/context.py	Removed default_catalog parameter from migrate calls

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