v1.2.13: Android Full Tunnel Mode requires credentials (fix #124)

Bug fix release. My v1.2.12 merge of Mode::Full bypassed the
deployment-ID + auth-key check on Android, but Full mode talks to
CodeFull.gs on Apps Script and needs those same credentials.

Users selecting "Full tunnel (no cert)" with empty fields would see
the VPN service bail silently instead of surfacing a clear "config
incomplete" error. Vahidlazio's fix changes the gate from
`mode == APPS_SCRIPT` to `mode != GOOGLE_ONLY` and removes the
Mode.FULL bypass in the Start button's enabled-state.

Also includes a UX refactor of the Deployment IDs editor (per-row
rows with add/remove buttons instead of raw newline-separated text),
making multi-deployment setups easier to manage on Android — useful
now that Full Tunnel Mode users routinely scale to 5+ deployments
per their Google accounts.

Android-only diff; Rust side is byte-identical to v1.2.12.

Cargo.lock

@@ -2186,7 +2186,7 @@ dependencies = [
 
 [[package]]
 name = "mhrv-rs"
-version = "1.2.12"
+version = "1.2.13"
 dependencies = [
  "base64 0.22.1",
  "bytes",