Match Entire's review verdict, serialize panel writes, stop cross-repo matches

The Code review card now says Fail whenever the agent reports a finding, as Entire's web view does; the findings gate still blocks only on high ones.

Fixes the two findings Code review raised on trail #1:

• Every refresh source writes the panel in turn, so overlapping refreshes no longer start from the same old panel and drop a workspace. Temporary files carry the process id.
• The panel falls back on name and branch only when terminals can't tell workspaces apart and exactly one entry matches, so a main/main workspace no longer shows another repo's trail.