Related issue

Closes #1914

Summary

Completes the SQL Server database-plugin portion of the identifier and literal escaping work.

• Consolidates bracket identifier and string-literal handling in SqlServerIdentifierProcessor and removes the parallel identifier utility.
• Preserves conditional quoteIdentifier(...) semantics while using quoteIdentifierAlways(...) for generated DDL and inherited builder/manager paths.
• Round-trips embedded and boundary brackets, handles qualified bracket/double-quoted identifiers, and uses locale-independent reserved-word matching.
• Adds quote-aware validation for parameterized/user-defined types and legal SQL Server defaults, while rejecting comments, statement boundaries, unbalanced expressions, and column-clause injection.
• Quotes database/schema/table/column/index names across metadata, export, update, template, drop, truncate, create, rename, and comment paths.
• Uses one SQL Server literal escaper for metadata comments and text/XML/geography value serialization without incorrectly doubling backslashes.

Affected surfaces

• Frontend / Web
• Backend / API / Storage
• Database plugin / Driver
• JCEF / Desktop packaging
• CI / Build / Release
• Documentation only

Verification

• Commands and results:
  • mvn -B -f chat2db-community-server/pom.xml -pl chat2db-community-plugins/chat2db-community-sqlserver -am clean test -DskipTests=false -Dmaven.test.skip=false -Dsurefire.failIfNoSpecifiedTests=false
  • Result: BUILD SUCCESS across 8 reactor modules; 188 tests passed in tested modules, including SQL Server 72/72, SPI 90/90, and tools 26/26.
  • git diff --check origin/main...HEAD: passed.
• Manual verification: Source-level generated-SQL review completed. No live SQL Server instance was used.
• UI evidence: N/A

Risk and compatibility

• Public API or stored data: No public API or stored-data schema change. Uses the existing shared ISQLIdentifierProcessor contract.
• Database or driver compatibility: Ordinary SQL Server identifiers retain conditional behavior; metadata-driven DDL now preserves bracket characters and qualified names. Legal defaults and custom/parameterized types are covered by regression tests.
• Network, privacy, or security: No network or privacy change. Reduces malformed SQL and identifier/literal injection risk in generated metadata, DDL, export, and DML paths.
• Community / Local / Pro boundary: Community SQL Server plugin only; Local and Pro consume the Community plugin behavior without product-specific code changes.
• Backward compatibility: Existing ordinary identifiers, defaults, types, and values retain their emitted form; embedded delimiters and apostrophes are now encoded consistently.

Reviewer map

• Start here: SqlServerIdentifierProcessor, SqlServerSqlGuards, then SqlServerSqlBuilder, SqlServerDBManager, and SqlServerColumnTypeEnum.
• Failure condition: Bracket quote/remove does not round-trip, legal defaults/types are rewritten, generated SQL contains raw metadata identifiers/literals, or backslashes are doubled in SQL Server strings.
• Rollback or disable path: Revert this PR; no migration or persisted-data rollback is required.

Contributor declaration

• I linked the Issue that defines this change.
• I tested the affected behavior and reported the actual results above.
• I did not include credentials, private data, or generated build output.
• I disclosed substantial AI assistance below, or this PR contains no substantial AI-generated code.

AI assistance: Substantial AI-assisted maintainer revision, review, and test expansion; all final changes were source-reviewed and verified with the commands above.