core: add OPENCODE_SKIP_MIGRATIONS flag to bypass database migrations

Allows users to skip automatic database migrations by setting the
OPENCODE_SKIP_MIGRATIONS environment variable. Useful for testing
scenarios or when manually managing database state.

packages/opencode/src/storage/db.ts

@@ -106,6 +106,11 @@ export namespace Database {
         count: entries.length,
         mode: typeof OPENCODE_MIGRATIONS !== "undefined" ? "bundled" : "dev",
       })
+      if (Flag.OPENCODE_SKIP_MIGRATIONS) {
+        for (const item of entries) {
+          item.sql = "select 1;"
+        }
+      }
       migrate(db, entries)
     }