refactor: consolidate pgflow compilation utilities into single migration (#515)

# Consolidate PgFlow Auto-Compilation Functions

This PR consolidates multiple temporary migration files related to PgFlow's auto-compilation functionality into a single migration file. The changes:

- Combine five separate migration files into a single file named `20251207150247_pgflow_auto_compilation.sql`
- Preserve all functionality including:
  - Flow shape comparison utilities
  - Flow creation from shape definitions
  - Flow deletion with data cleanup
  - Flow compilation with development/production modes
  - Advisory locking for concurrent compilation safety
  - Support for flow and step-level options

The consolidated migration maintains all the same functionality while simplifying the migration history and making the codebase more maintainable.

Author: jumski