fix(branding): use the Caduceus ☤ (U+2624), not the Rod of Asclepius ⚕ (U+2625)

Every inline glyph — CLI banner/status bar/response labels/goodbye, setup
and doctor boxes, gateway update prompts, WhatsApp reply prefix, TUI theme,
locale strings and the docs — used ⚕, the staff of Asclepius (medicine).
Hermes carries the Caduceus ☤. The ASCII-art logo was already correct.

Mechanical swap across 60 files (no logic change); both glyphs are
East-Asian-width Neutral so no layout shifts. Skins that set their own
`response_label` / `goodbye` are unaffected.

Direction from PR #7064 (@bixycler), the earliest of #7064 / #9611 / #15574,
redone against current main.

Fixes #9565

locales/en.yaml

@@ -400,7 +400,7 @@ gateway:
     not_git_repo:            "✗ Not a git repository — cannot update."
     hermes_cmd_not_found:    "✗ Could not locate the `hermes` command. Hermes is running, but the update command could not find the executable on PATH or via the current Python interpreter. Try running `hermes update` manually in your terminal."
     start_failed:            "✗ Failed to start update: {error}"
-    starting:                "⚕ Starting Hermes update… I'll stream progress here."
+    starting:                "☤ Starting Hermes update… I'll stream progress here."
 
   usage:
     rate_limits:              "⏱️ **Rate Limits:** {state}"