fix: index name quotation

[tianzhou]

Fix #80

[Copilot]

Pull Request Overview

This PR fixes index name quotation issues (GitHub issue #80) by ensuring that index names requiring quotation are properly quoted when generating SQL statements. The fix addresses cases where index names contain spaces, special characters, mixed case, or reserved keywords.

• Updates SQL generation code to properly quote index names using ir.QuoteIdentifier()
• Adds comprehensive test coverage with various index naming scenarios
• Ensures compatibility between pgschema output and PostgreSQL's quoting requirements

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
testdata/dump/issue_80_index_name_quote/raw.sql	Test data with various index naming scenarios requiring quotation
testdata/dump/issue_80_index_name_quote/pgschema.sql	Expected pgschema output with properly quoted index names
testdata/dump/issue_80_index_name_quote/pgdump.sql	Reference pg_dump output for comparison
testdata/dump/issue_80_index_name_quote/manifest.json	Test case metadata and description
internal/plan/rewrite.go	Fixed index name quoting in DROP and ALTER INDEX statements
internal/diff/index.go	Fixed index name quoting in CREATE INDEX statements
cmd/dump/dump_integration_test.go	Added integration test for the index name quotation fix

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