fix: do not mistake a name beginning with 127 for the phone itself

A server called something like 127.books.home is a name, not an
address, and it was being read as the phone talking to itself — which
is the one case the permission check deliberately lets through. A
reader with such a server would have got the timeout rather than the
prompt. All four parts of an address now have to be numbers before it
is treated as one.

app/src/main/kotlin/com/chmouel/liseur/data/remote/LocalNetworkAddress.kt

@@ -178,7 +178,7 @@ object LocalNetworkAddress {
     }
 
     private fun isV4Loopback(host: String): Boolean =
-        host.split('.').let { it.size == 4 && it.first().toIntOrNull() == 127 }
+        isLiteral(host) && ':' !in host && host.substringBefore('.').toInt() == 127
 
     private fun isLiteral(host: String): Boolean =
         ':' in host || host.split('.').let { parts ->

app/src/test/kotlin/com/chmouel/liseur/data/remote/LocalNetworkAddressTest.kt

@@ -90,6 +90,24 @@ class LocalNetworkAddressTest {
      * trailing dot as part of it would send an mDNS address off to be
      * resolved by mDNS, which is what the permission is blocking.
      */
+    /**
+     * A name is not an address because it starts with a number. Reading
+     * `127.books.home.local` as loopback would exempt a server on the
+     * reader's own network from the one check that gets them prompted.
+     */
+    @Test
+    fun `a name that begins with 127 is still a name`() = runTest {
+        assertTrue(
+            LocalNetworkAddress.isLocal("http://127.books.home.local:8083", resolver = refusing),
+        )
+        assertTrue(
+            LocalNetworkAddress.isLocal(
+                "http://127.books.example.com:8083",
+                resolver = { listOf("192.168.1.20") },
+            ),
+        )
+    }
+
     @Test
     fun `a name written out to the root label is the same name`() = runTest {
         assertTrue(LocalNetworkAddress.isLocal("http://books.local.:8083", resolver = refusing))