feat: add multi-runtime support (coord run, prdy --codex) and next-task capsule

- coord/prdy subcommands now accept --claude/--codex runtime flags
- New `mosaic coord run` generates continuation context and launches
  selected runtime, replacing manual copy/paste workflow
- Next-task capsule (.mosaic/orchestrator/next-task.json) provides
  machine-readable execution context for deterministic session launches
- Codex strict orchestrator profile added to runtime/codex/RUNTIME.md
- Orchestrator protocol updated with between-session run flow
- New smoke-test.sh for orchestration behavior verification

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tools/orchestrator/mission-init.sh

@@ -270,6 +270,9 @@ fi
 
 # ─── Report ──────────────────────────────────────────────────────────────────
 
+runtime_cmd="$(coord_launch_command)"
+run_cmd="$(coord_run_command)"
+
 echo ""
 echo -e "${C_GREEN}${C_BOLD}Mission initialized: $NAME${C_RESET}"
 echo ""
@@ -280,4 +283,4 @@ echo -e "  ${C_CYAN}Manifest:${C_RESET}    $manifest_path"
 echo -e "  ${C_CYAN}Scratchpad:${C_RESET}  $sp_file"
 echo -e "  ${C_CYAN}Tasks:${C_RESET}       $tasks_path"
 echo ""
-echo "Next: Launch an agent session with 'mosaic claude' or generate a prompt with 'mosaic coord continue'"
+echo "Next: Resume with '$run_cmd' (or launch directly with '$runtime_cmd')."