fix(beads): set routing mode to explicit instead of auto

The routing.mode was defaulting to 'auto', which uses git remote URL
to detect user role. Non-SSH URLs can cause mail and issues to be
routed to ~/.beads-planning instead of the local .beads directory.

Setting routing.mode to 'explicit' disables auto-routing entirely,
keeping all issues in the expected local directory.

Fixes: x-kho

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.beads/config.yaml

@@ -59,4 +59,6 @@ sync-branch: "beads-sync"
 # - linear.url
 # - linear.api-key
 # - github.org
-# - github.repo
+# - github.repo
+
+routing.mode: "explicit"