fix: don't archive gitleaks-allow response before gate reads it

The TUI was calling archive_proposal for gitleaks-allow immediately
after write_response, moving the response file to processed/ within
microseconds. The git-gate shell loop polls queue_dir for the response
file every second — it never sees it and hangs until timeout.

capability-block is handled by the MCP sidecar which archives after
reading; gitleaks-allow is handled by the shell gate which archives
after processing. Let the gate own the archive step.

bot_bottle/cli/supervise.py

@@ -157,7 +157,7 @@ def approve(
         qp, action=status, notes=notes,
         diff_before=diff_before, diff_after=diff_after,
     )
-    if qp.proposal.tool in (TOOL_CAPABILITY_BLOCK, TOOL_GITLEAKS_ALLOW):
+    if qp.proposal.tool == TOOL_CAPABILITY_BLOCK:
         archive_proposal(qp.queue_dir, qp.proposal.id)