Support PostgreSQL tagged dollar strings and preserve literal bodies

[minleejae]

Tagged PostgreSQL strings such as $json$…$json$ currently fail to parse or become column references. Recognize them as StringValue while preserving the exact delimiter, whitespace and literal contents:

SELECT $json$[{"some":"json","with":"properties$"}]$json$::jsonb;

Reuse a shared delimiter recognizer in the lexer, StringValue and routine-body boundary detection. The lexer reads the original character stream with a linear delimiter matcher, handles longest-match identifier tokens, and updates token end positions. Dollar-quoted values keep doubled apostrophes unchanged in getNotExcapedValue(). A tagged routine body remains one token, so a following SQL statement is preserved.

Tagged quoting is disabled by default to preserve identifier parsing. Enable it with withDialect(Dialect.POSTGRESQL) or withDollarQuotedStringTags(true); an explicit withDollarQuotedStringTags(false) after the PostgreSQL preset disables it again. Ordinary dollar-containing identifiers, positional parameters and untagged $$ literals remain supported.

Validation:

• Full Gradle check and Maven verify.
• Re-enabled the existing tagged-string regression test.
• Empty/Unicode tags, whitespace and CRLF preservation, embedded dollar signs and other tags, casts, bind parameters, quoted identifiers, default/non-PostgreSQL identifier parsing, explicit opt-in and PostgreSQL preset overrides.
• Model/deparser round-trips, token positions, long Reader/InputStream inputs with overlapping delimiter prefixes, unterminated tags, and routine bodies followed by another statement.
• Syntax follows the PostgreSQL dollar-quoting documentation.

Fixes #2233.

[manticore-projects]

Good work, just minor German nit picking.

[manticore-projects]

고맙습니다!

[manticore-projects]

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