fix(team-profile): importing a profile stops at the first failed save and loses the count #1759

Problem

`TeamProfile.importInto` (lib/core/team/team_profile.dart) calls `db.addConnection` in a loop with no error handling. `addConnection` rolls its own row back and rethrows when the secret write fails (keyring locked or unavailable). The loop then aborts: connections before the failing one stay saved, the rest are never tried, the returned "added" count is lost, and the caller gets only the exception.

Expected

Try every row, collect the failures, and report "N added, M failed" with the first error, so a keyring problem on one row neither hides the rows that were saved nor skips the rest.

Related

• Same family as the silent failure of the creation flows fixed in fix(connections): report and log a failed save of a new connection #1757.
• Other direct `addConnection` callers without handling: `lib/core/platform/file_launch_service.dart`, `lib/core/demo/demo_playground_service.dart`, the scratch connection in `lib/features/main_screen/main_screen_dialogs.dart`. Their failures show up as "Failed to open file" or not at all.

Found in the review of #1757.