Add MATCHES / * MATCHES SQL syntax for full-text search

[tlee732]

Summary

• Add MATCHES and * MATCHES as new SQL syntax for full-text search, replacing verbose indexquery/indexqueryall legacy syntax
• WHERE content MATCHES 'query' → single-column search (maps to IndexQueryExpression)
• WHERE * MATCHES 'query' → all-fields search (maps to IndexQueryAllExpression)
• Case-insensitive keyword (MATCHES, matches, Matches all work)
• Legacy indexquery/indexqueryall syntax remains fully supported
• Update prettyName/sql/toString on expression classes to use new naming
• Register MATCHES keyword in IndexTables4SparkExtensions SQL parser

Tests (14 total):

• 7 parser-level tests (simple, case-insensitive, backtick columns, complex Tantivy syntax, qualified names, * MATCHES basic + case-insensitive)
• 2 end-to-end small dataset tests (MATCHES and * MATCHES)
• 2 backward compatibility parser tests (indexquery, indexqueryall)
• 1 all-syntax comparison test (3-row dataset, 4 syntax variants cross-checked)
• 1 scale test (100k rows, 3 query types, all 4 syntaxes produce identical results)
• 1 compound WHERE clause test with 6 sub-cases covering the full matrix:

	AND standard filter	AND MATCHES	OR standard filter	OR MATCHES
MATCHES	✅	✅	✅	✅
* MATCHES	✅	n/a	✅	n/a

Test plan

• MatchesSyntaxParserTest — 14/14 passed
• All compound WHERE clause sub-cases cross-checked against legacy syntax equivalents
• Full make test run (320 local test classes)

🤖 Generated with Claude Code