feat(ql): add DELETE/UPDATE/SELECT statements with ANTLR grammar

[abalam666]

Summary

• Add DELETE, UPDATE, and SELECT statement support to WebdaQL, fully defined in the ANTLR grammar (.g4) and parsed via generated visitor methods
• Make all keywords case-insensitive natively in the lexer using fragment-per-letter approach (e.g. delete, Delete, DELETE all work)
• Add allowedFields validation for SELECT field lists and UPDATE SET assignment targets
• Add ql-ts-plugin package for lightweight field extraction in IDE contexts

Details

• Grammar: WebdaQLLexer.g4 defines case-insensitive tokens; WebdaQLParser.g4 adds deleteStatement, updateStatement, selectStatement rules with assignmentList and fieldList
• Runtime: ExpressionBuilder visitor handles all statement types — no hand-written string parsing needed. The parse() function passes the full query to ANTLR
• Breaking: implicit SELECT (bare field list without SELECT keyword) is removed — SELECT keyword is now required
• Repositories: MemoryRepository.query() passes getAllowedFields() to parse() for field validation

Syntax

-- DELETE
DELETE WHERE status = 'inactive' LIMIT 100

-- UPDATE
UPDATE SET status = 'active', age = 30 WHERE name = 'John'

-- SELECT
SELECT name, age WHERE status = 'active' ORDER BY name ASC LIMIT 10 OFFSET 'token'

-- Plain filter (unchanged)
status = 'active' AND age > 18

[loopingz]

Grammar should be updated instead of manual parsing