* Implement migration safety rules:
- MIG001: Warn on CREATE INDEX without CONCURRENT.
- MIG002: Warn on ALTER TABLE ADD COLUMN NOT NULL without DEFAULT.
- MIG003: Warn on ALTER TABLE ADD CONSTRAINT without NOT VALID.
* Implement naming conventions rules:
- NAM001: Warn on non-snake_case table names.
- NAM002: Warn on non-snake_case column names in CREATE TABLE.
- NAM003: Warn on non-snake_case function names.
* Add test fixtures for all new rules.
* Implemented `-d`/`--diff` flag to print unified diffs.
* Added `unifiedDiff` function for generating diffs.
* Config discovery now merges fields from `.pgtidy.yaml`.
* Implemented formatting for BEGIN...END blocks in PL/pgSQL.
* Added logic to handle indentation and blank lines.
* Introduced tests for broken formatting cases.
warkanum