Add interactive workflows TUI manager

[andrei-hasna]

Summary

• add an interactive /workflow and /workflows manager with Specs, Runs, and Approvals tabs
• show loading, error, empty, active-run, and completed-run action states with focused snapshots
• wire inspect/run/pause/resume/stop through existing workflow RPC events while leaving unsupported delete and workflow-scoped approval review actions disabled
• add /workflows as a slash alias and keep workflow draft creation blocked while a task is running

Validation

• cd codex-rs && UV_CACHE_DIR=/tmp/uv-cache-codewith just fmt
• cd codex-rs && just test-fast -p codex-tui workflow_manager workflows_alias workflow_list workflow_run_controls workflow_draft
• cd codex-rs/tui && cargo insta pending-snapshots (no pending snapshots)
• cd codex-rs && just fix -p codex-tui
• staged secret scan: no credential-value matches

Notes

• cd codex-rs && just test -p codex-tui was attempted before the final lint pass and failed on pre-existing/unrelated snapshot drift: changelog release notes now show 0.1.55, and status/terminal-title preview tests in this worktree report tmp where older snapshots expect project/my-project. The new workflow manager tests passed in the focused gate.
• Follow-up todos were created for the missing delete RPC/TUI enablement and workflow-scoped approval review integration.

[andrei-hasna]

Closing as superseded by #211. Replacement #211 consolidates the current TUI/thread-routing stack and explicitly supersedes this PR. Please continue review on #211.