feat: add plpgsql-parser package for combined SQL + PL/pgSQL parsing

[pyramation]

feat: add plpgsql-parser package for combined SQL + PL/pgSQL parsing

Summary

Adds a new plpgsql-parser package that provides a unified API for parsing SQL scripts containing PL/pgSQL functions. The package combines the SQL parser and PL/pgSQL parser, automatically detecting and hydrating PL/pgSQL function bodies.

Key features:

• parse(sql) - Auto-detects CREATE FUNCTION statements with LANGUAGE plpgsql and hydrates them
• transform(sql, callback) - Pipeline for parse → modify → deparse workflows
• deparseSync(parsed) - Converts modified AST back to SQL with pretty printing
• Re-exports underlying primitives (parseSql, parsePlpgsqlBody, deparseSql, etc.) for power users

Updates since last revision

• Updated README.md with pretty headers (logo, CI badge, license badge, version badge) to match plpgsql-deparser style
• Added experimental warning with links to related packages (pgsql-parser, plpgsql-deparser)

Review & Testing Checklist for Human

• Verify workspace dependencies for publishing - The package uses workspace:* for pgsql-deparser and plpgsql-deparser. Confirm the publish pipeline rewrites these to actual version numbers.
• Test with multiple PL/pgSQL functions - The current tests only cover single-function scenarios. Verify behavior when a script contains multiple CREATE FUNCTION statements.
• Review any type usage - PlpgsqlFunctionData.hydrated is typed as any (types.ts:15). Consider if stronger typing is needed for downstream consumers.
• Test async transform() function - Only transformSync is tested; the async variant should be verified manually.
• Verify error handling - extractFunctionInfo silently returns null on parse errors (parse.ts:90-92). Confirm this behavior is acceptable vs surfacing errors.

Recommended test plan:

1. Run npm test in packages/plpgsql-parser - all 7 tests should pass
2. Try parsing a script with 2+ PL/pgSQL functions and verify both are detected
3. Try the transform API to rename a function and verify the output SQL is correct
4. Build the package with npm run build and verify dist output looks correct

Notes

• This is a thin orchestration layer that composes existing packages (@libpg-query/parser, pgsql-deparser, plpgsql-deparser)
• The deparseSync function uses require() inside the function body (deparse.ts:85) to avoid import conflicts - this is intentional but worth noting
• Requested by Dan Lynch (@pyramation)
• Link to Devin run: https://app.devin.ai/sessions/50192c7bb0454b26845853867bd795ce

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