Keep resumed session handling exhaustive

The resumed session command matcher now owns every /session variant in one arm so adding supported actions does not leave a redundant fallback that triggers unreachable-pattern warnings.\n\nConstraint: G010 session hygiene verification requires clean focused tests around resume/session recovery UX.\nRejected: Leave the warning in place | it obscures real regressions in the focused recovery checks.\nConfidence: high\nScope-risk: narrow\nDirective: Keep new /session resume-mode actions inside run_resumed_session_command rather than duplicating match arms.\nTested: cargo test -p rusty-claude-cli context_window_preflight_errors_render_recovery_steps\nNot-tested: full workspace test suite

Co-authored-by: OmX <omx@local>

rust/crates/rusty-claude-cli/src/main.rs

@@ -4170,7 +4170,6 @@ fn run_resume_command(
         | SlashCommand::Fast
         | SlashCommand::Exit
         | SlashCommand::Summary
-        | SlashCommand::Session { .. }
         | SlashCommand::Desktop
         | SlashCommand::Brief
         | SlashCommand::Advisor