Subagent event JSONL files and rehydration metadata were stored in the
shared ~/.openclaw/web-chat/ directory regardless of the active workspace
profile, while parent chat sessions were correctly profile-scoped.
Move subagent event persistence into the profile-scoped web-chat dir
(web-chat-<profile>/subagent-events/) and add a profile-local
subagent-index.json for fast rehydration after page refresh. The shared
gateway registry (~/.openclaw/subagents/runs.json) remains the fallback
source. Existing events in the legacy shared path are still readable as
a migration fallback.
