feat(glossary): read the mesh axis at a glance

A padlock and an open padlock differ by a few pixels in a job title, which
is where the axis is read most often. A tunnel and a road do not.

Every label derives from here, the plan table's own column header included,
so the two entries carry the change.

utils/symbol_glossary.py

@@ -34,8 +34,8 @@ SYMBOLS: dict[str, str] = {
     "swarm": "🐝",
     "tor": "🧅",
     "clearnet": "🌐",
-    "vpn": "🔒",
-    "direct": "🔓",
+    "vpn": "🚇",
+    "direct": "🛣️",
     "stack": "🥞",
     "host": "💻",
     "row": "🔢",