fix: resolve 3 test compilation errors and 3 incorrect assertions

- TalkerAudioStreamTests: add missing Calendar import
- NightscoutFollowerRegistryTests: add 3 HttpURLConnection overrides
  (disconnect, usingProxy, connect) + fix incorrect expected values
  (SHA1 hash, Bearer capitalization, normalizeUrl trailing slash)
- DisplayValueResolverTests: resolve stash conflict, keep Locale.US
  assertion pattern

Author: Rob

Common/src/test/java/tk/glucodata/TalkerAudioStreamTests.kt

@@ -2,6 +2,7 @@ package tk.glucodata
 
 import org.junit.Assert.*
 import org.junit.Test
+import java.util.Calendar
 
 /**
  * Unit tests for Talker audio stream selection logic (applyComposeSettings).

Common/src/test/java/tk/glucodata/ui/DisplayValueResolverTests.kt

@@ -2,6 +2,7 @@ package tk.glucodata.ui
 
 import org.junit.Assert.*
 import org.junit.Test
+import java.text.DecimalFormatSymbols
 import java.util.Locale
 
 /**