fix(function): reject binary regexp operands and add match type overloads

[ck89119]

What type of PR is this?

• API-change
• BUG
• Improvement
• Documentation
• Feature
• Test and CI
• Code Refactoring

Which issue(s) this PR fixes:

issue #25299

What this PR does / why we need it:

MySQL rejects statically typed binary-character-set operands used by REGEXP, NOT REGEXP, and the REGEXP_* functions with error 3995 (HY000). MatrixOne previously let the generic fixed-type matcher cast BINARY, VARBINARY, and BLOB operands to VARCHAR before regexp validation, so these expressions executed instead of failing.

This change:

• validates static binary string operands after overload resolution but before implicit regexp casts;
• shares the validation across the regexp operators and REGEXP_LIKE, REGEXP_INSTR, REGEXP_SUBSTR, and REGEXP_REPLACE;
• returns MySQL-compatible error 3995 / SQLSTATE HY000, including the correct function name and operand order;
• follows MySQL's PARAM_ITEM and NULL_ITEM exceptions, so SQL/binary-protocol prepared parameters, binary NULL, and explicit character casts remain valid;
• keeps prepared execution on the existing reusable-plan path without a regexp-specific plan scan or extra deep copy;
• adds the missing match_type overloads for REGEXP_INSTR, REGEXP_SUBSTR, and REGEXP_REPLACE, including c, i, m, n, and u behavior;
• aligns optional-argument edge behavior with MySQL for UTF-8 character positions, newline modes, empty patterns, position/occurrence boundaries, return_option, and replacement capture expansion;
• covers binary literals, expressions, columns, prepared parameters, NULL/empty/invalid-byte cases, and normal text controls.

An explicit empty match_type preserves MatrixOne's existing case-sensitive default. Matching MySQL's collation-derived default would require propagating collation metadata into the function executor and is outside this change.

Validation:

• make build
• .agents/skills/mo-dev/scripts/mo-cgo-test ./pkg/common/moerr ./pkg/sql/plan/function ./pkg/sql/plan ./pkg/frontend -count=1
• .agents/skills/mo-dev/scripts/mo-cgo-test ./pkg/tests/issues -run '^TestIssue25299RegexpRejectsBinaryCharset$' -count=1 -timeout 5m
• targeted distributed BVT: 114/114 passed
• git diff --check
• mo-self-review on the complete diff