Remove mssql references

[eighttrigrams]

#74

[Copilot]

Pull request overview

This pull request removes all MSSQL (Microsoft SQL Server) database support from the Gitea codebase. The changes comprehensively eliminate MSSQL-specific code paths, configurations, tests, and documentation references.

• Removes MSSQL database type support and related connection handling
• Eliminates MSSQL-specific database migration and test infrastructure
• Updates documentation and locale strings to remove MSSQL references

Reviewed changes

Copilot reviewed 70 out of 73 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
web_src/js/features/install.ts	Removed MSSQL default database host configuration
tests/test_utils.go	Removed MSSQL database initialization logic for tests
tests/mssql.ini.tmpl	Deleted MSSQL test configuration template file
tests/integration/migration-test/migration_test.go	Removed MSSQL-specific database restore logic
tests/integration/db_collation_test.go	Removed MSSQL collation testing and helper functions
tests/integration/README.md, tests/integration/README_ZH.md, tests/e2e/README.md	Removed MSSQL test setup instructions
templates/admin/self_check.tmpl	Removed MSSQL database fix message template
options/locale/*.ini	Removed MSSQL from database requirements and fix instructions across all locales
modules/setting/database.go	Removed MSSQL from supported database types and removed MSSQL connection/parsing functions
models/unittest/fixtures_loader.go	Removed MSSQL-specific identity column handling
models/repo/fork.go, models/git/branch.go, models/git/commit_status.go, models/git/protected_branch.go	Removed MSSQL references from comments and removed MSSQL-specific functions
models/migrations/*	Removed MSSQL-specific migration code across multiple migration files
models/db/*.go	Removed MSSQL builder dialect, error handling, collation support, and database conversion functions
go.mod, go.sum	Removed MSSQL driver dependency
custom/conf/app.example.ini, custom/options/locale/locale_en-US.ini	Removed MSSQL configuration examples
cmd/dump.go, cmd/doctor_convert.go	Removed MSSQL from database syntax options and doctor convert command
Makefile, .github/workflows/pull-db-tests.yml	Removed MSSQL test targets and CI workflow
.gitea/issue_template.md	Removed MSSQL from database options in issue template

Comments suppressed due to low confidence (3)

models/migrations/v1_22/v286.go:1

• The 'fmt' import is still needed for the remaining Sprintf calls but 'errors' was removed. However, this results in an unused import since 'errors' was imported but is no longer used after the MSSQL code removal.
  models/migrations/v1_22/v283.go:1
• The 'fmt' and 'xorm.io/xorm/schemas' imports were removed but they may still be needed. Verify that these imports are not used elsewhere in the file.
  models/migrations/v1_22/v294.go:1
• The 'fmt' and 'xorm.io/xorm/schemas' imports were removed. Ensure these are not used elsewhere in the file.

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[Copilot]

The 'base' import from 'code.gitea.io/gitea/models/migrations/base' was removed, but verify it's not needed for other code in this file.

[Copilot]

The comment explaining the x509negativeserial godebug flag was removed. This comment provided important context about why this flag was needed (for MSSQL's negative serial number certificates). While the MSSQL support is removed, if this flag is still required for other reasons, the comment should be updated to reflect the current rationale rather than completely removed.

Suggested change

	// Enable legacy support for X.509 certificates that use negative serial numbers.
	// Kept for interoperability with existing deployments that rely on such certificates.
	// See Go's x509negativeserial GODEBUG documentation for details.

[eighttrigrams]

leave the comment as is, that is, leave the why in place, and simply add that we removed mssql support