chore(release): v0.4.13 (versionCode 40) — waitlist retry queue (#166)

* chore(release): v0.4.13 (versionCode 40) — waitlist retry queue reaches users

Ships 2f81d34 (#165): failed waitlist signups are persisted on-device and
retried on app foreground instead of silently falling back to mailto.
Until this Play release, no user is running that fix.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

* fix(waitlist): stamp the app version into the mailto escape hatch

AGE-100 asks for the post-release mailto count "split by app version where the
mail body allows it". It did not allow it: the body was "Sign me up!\n\nEmail: x"
and nothing else, so a mail from an unreachable pre-v0.4.8 sideload is byte-identical
to one from a current build whose retry queue leaked. Those two readings have
opposite meanings — the first is the known permanent cohort, the second is a defect.

Now the escape hatch appends "App: OpenCode Mobile v<version>" (app.json, same
source Sentry uses). Absence of the line == pre-v0.4.13 build. waitlist.ts stays
free of react-native/JSON imports; the screen injects the version.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

---------

Co-authored-by: engineer <engineer@macbookpro.lan>
Co-authored-by: Paperclip <noreply@paperclip.ing>

app.json

@@ -2,7 +2,7 @@
   "expo": {
     "name": "OpenCode",
     "slug": "opencode-mobile",
-    "version": "0.4.12",
+    "version": "0.4.13",
     "orientation": "portrait",
     "scheme": "opencode",
     "userInterfaceStyle": "automatic",
@@ -35,7 +35,7 @@
     },
     "android": {
       "package": "cc.agentlabs.opencode",
-      "versionCode": 39,
+      "versionCode": 40,
       "usesCleartextTraffic": true,
       "adaptiveIcon": {
         "foregroundImage": "./assets/adaptive-icon.png",