chore(test-isolation): tolerate live fusion app noise on shared HOME

Local `pnpm test:isolated` was failing because a concurrently-running
fusion app continually mutates `~/.fusion` (databases, agent sessions,
memory, automations, plugins, logs). Filter those runtime-owned paths
from the protected-dir signature, widen the baseline-stability sampling
window, and re-sample on suspected violations so transient app activity
doesn't masquerade as test pollution.

Tests still cannot legitimately write into these paths — they're skipped
because the *running app* is expected to.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/dashboard-guide.md

@@ -72,6 +72,10 @@ Quick Chat is an optional floating panel for fast, project-scoped assistant conv
 
 Mailbox view shows inbox/outbox communication threads and unread state.
 
+- Inbox renders one row per message (no sender-based collapsing)
+- Visible message history/threading is driven by explicit `message.metadata.replyTo.messageId` links
+- Separate top-level messages from the same sender remain independent in the inbox and detail pane
+
 ![Mailbox view](./screenshots/mailbox-view.png)
 
 ## Interactive Terminal