Pause and resume Planner workflows through the workflow tool, and pulse live runs

Stop Planner reported that it paused the workflows, but they kept
running: the /workflow slash command reports its outcome only through
ui.notify, which a headless session drops, so a refused or no-op pause
looked like success. Run pause and resume through the session's own
workflow tool with a real tool context instead, so the outcome returns
as a result and a failure reaches the chat transcript.

The run card's spinner never animated because chat-tool-loader has no
animation in the web app. Live runs and running stages now show a
pulsing dot that stays still under reduced motion.

Assistant-model: Claude Opus 5.5
Assistant-workflow: inline
Assistant-verification: bun test passed: 1754 pass, 2 PostgreSQL skips, 0 fail, including run control through the workflow tool and its failure path
Assistant-verification: bun run types passed: all workspaces
Assistant-verification: bun run ci passed: dprint, oxlint, tokens, type scale, Impeccable (no new findings)
Assistant-verification: agent-browser E2E failed before this change: Stop Planner posted "paused its workflows" while the run card stayed running and no pause was recorded
User-preference: Live workflow runs in Chopin show a pulsing dot rather than a spinner
Co-authored-by: Alex Lavaee <lavaman131@github.com>