feat(deparser): add type-name quoting policy for minimal quoting in type positions

[pyramation]

feat(deparser): add type-name quoting policy for minimal quoting in type positions

Summary

This PR fixes over-quoting of user-defined schema-qualified type names that contain PostgreSQL keywords. Previously, types like myschema.json, custom.int, and myapp.boolean were being emitted as myschema."json", custom."int", myapp."boolean" because the deparser applied strict identifier quoting to all type name parts.

The fix introduces a new "type-name quoting policy" that is less strict than standalone identifier quoting but still quotes RESERVED_KEYWORD:

• Before: SELECT '{"d":4}'::myschema."json"
• After: SELECT '{"d":4}'::myschema.json

Changes:

• Add quoteIdentifierTypeName() function that only quotes RESERVED_KEYWORD (allows COL_NAME_KEYWORD and TYPE_FUNC_NAME_KEYWORD unquoted)
• Add quoteTypeDottedName() for schema-qualified type names
• Update TypeName handler to use new quoting for non-pg_catalog types
• Add test fixtures for type casts and user-defined schema-qualified types
• Update QUOTING-RULES.md with documentation

Review & Testing Checklist for Human

• Verify PostgreSQL grammar correctness: Confirm that PostgreSQL actually allows COL_NAME_KEYWORD (json, int, boolean) and TYPE_FUNC_NAME_KEYWORD (interval) unquoted in type positions. Test by running the generated SQL against a real PostgreSQL instance.
• Check edge cases with RESERVED_KEYWORD: Verify that types like myschema.select still get quoted correctly as myschema."select" (the snapshots suggest this works, but manual verification recommended)
• Review the single-line change in deparser.ts: Line 1975-1977 is the critical change - verify quoteTypeDottedName() is the right choice for ALL non-pg_catalog types

Recommended test plan:

1. Run pnpm test in packages/deparser - quoting tests should pass
2. Parse and deparse SQL with user-defined schema-qualified types containing keyword names
3. Execute the generated SQL against PostgreSQL to confirm it parses correctly

Notes

• Pre-existing test failures (7 tests) related to case sensitivity (AlertLevel vs alertlevel) are unrelated to this change
• This is part of a larger effort to implement minimal quoting rules across the deparser

Link to Devin run: https://app.devin.ai/sessions/713c834a5761453297e17345e1c1fd47
Requested by: Dan Lynch (@pyramation)

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