[KeyffMS]

R2g

Small move-only continuation of #83 R2.

Scope:

• move the connection-specific session_fault_for_connect_error helper from crates/lantern-app/src/application.rs into crates/lantern-app/src/application/connection.rs;
• remove only the now-unused root imports;
• keep exactly one ApplicationState and the top-level ApplicationState::reduce in application.rs.

Safety/architecture:

• no behavior changes intended;
• write confirmation and restore confirmation remain unchanged in application.rs, so the existing exact-confirmation architecture gate continues to cover them directly;
• no scheduler/budget/fairness/QueueFull changes;
• no write/restore/session authority changes and no conformance/gate weakening.

Refs #83