fix(omp): resume by mode, not silently as claude, and support --continue

resumeHistorySession() never sent mode when recreating a session from a
history/session-manager row, so the server default silently opened a
plain Claude session for every non-claude row -- reproduced live: OMP
rows spawned Claude sessions on click. Thread the row's mode through
every call site (welcome list, session manager, mobile overview) and
only send the Claude-specific resumeSessionId for claude rows.

Codeman has no live PTY-reattach outside server boot, and it's moot for
OMP anyway (exiting it kills the pane's only process), so route the
non-claude relaunch through each CLI's own continue-most-recent flag
instead of a context-free fresh start. OMP never got one: buildOmpCommand
only implemented --model/--resume despite omp --help documenting
-c/--continue. Added continueSession to OmpConfig end-to-end (type,
schema, builder) mirroring the existing opencode/pi/grok/deepseek
fields, and wired resumeHistorySession to use it.

Verified live: told a real omp session a secret, exited it, closed the
tab without killing tmux, relaunched with --continue in the same
directory, and had it recall the secret.

src/types/session.ts

@@ -350,6 +350,8 @@ export interface OmpConfig {
   model?: string;
   /** Resume a previous conversation (passed via --resume). */
   resumeSessionId?: string;
+  /** Continue the most recent session in this directory (passed via --continue). */
+  continueSession?: boolean;
 }
 
 /**