feat(db): add conflict tolerant inserts to query builder and QBMapper

[Koc]

Summary

• Adds IQueryBuilder::ignoreConflictsOnInsert() to mark an INSERT as
  conflict tolerant. The SQL rewrite happens in getSQL() via a new
  Adapter::getInsertIgnoreSqlTransformer() (INSERT IGNORE for
  MySQL/MariaDB, ON CONFLICT DO NOTHING for PostgreSQL/SQLite, plain
  INSERT as fallback), so typed parameters and shard-key hints survive.
• Refactors Adapter*::insertIgnoreConflict() to use the flag instead of
  editing the SQL string and calling the connection directly.
• Adds QBMapper::insertIgnoreConflict(Entity $entity): int, porting the
  capability of the Collectives TInsertIgnoreConflict trait into core,
  returning the number of inserted rows (0 when a conflicting row exists).

Tests

• tests/lib/DB/QueryBuilder/QueryBuilderTest.php: SQL transform per
  platform, end-to-end conflict insert, LogicException on non-INSERT.
• tests/lib/AppFramework/Db/QBMapperTest.php / QBMapperDBTest.php:
  typed parameter mapping, conflict returns 0 without overwriting the row.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

AI (if applicable)

• The content of this PR was partly or fully generated using AI