Fix "table already exists" crash on startup when deploying consolidated baseline migration

[Copilot]

When migrations were consolidated into a single 20260313031641_NewDatabase baseline, already-deployed databases have all the tables but no record of that migration ID in __EFMigrationsHistory. Migrate() then tries to CREATE TABLE AuditLogs and crashes.

Changes

Program.cs — adds MarkBaselineMigrationIfTablesExist(db) called before Migrate():

• Checks INFORMATION_SCHEMA.TABLES for ≥ 2 of AuditLogs, Institutions, DataProducts to confirm an existing schema (multi-table guard avoids false-positives)
• Uses IHistoryRepository.GetCreateIfNotExistsScript() to create __EFMigrationsHistory if absent (covers databases bootstrapped via EnsureCreated())
• Inserts the baseline migration record via IHistoryRepository.GetInsertScript() so Migrate() skips it
• Reads the EF Core product version dynamically from the assembly rather than hardcoding
• Returns early on a fresh database, leaving normal Migrate() behaviour intact

// Before Migrate(), mark the consolidated baseline as already applied
// if the schema pre-dates migration consolidation.
MarkBaselineMigrationIfTablesExist(db);
db.Database.Migrate();