fix: more bug fixes — specs, examples, JNI signatures, constants

Spec fixes:
- Remove wrong-type constants: UuidDefault (UUID, not int), AuthorityUri
  (Uri, not int), Uri.EMPTY (Uri, not int)
- Add 13 missing DIRECTORY_* string constants to environment spec
- Add SpeechRecognizer ERROR_NETWORK/ERROR_NETWORK_TIMEOUT constants
  (renamed to RecognizerError* to avoid collision with TTS constants)
- Fix NetworkCapabilities unexported type (workCapabilities -> NetworkCapabilities)

Example fixes:
- alarm: fix comma-separated permissions, gate Set() on canSchedule
- toast: actually show the toast instead of discarding the object
- pdf: free Canvas/Paint GlobalRefs
- lights: free manager GlobalRef
- speech: increase TTS init wait to 3s

Generated code fixes (via template/regeneration):
- Fix CharSequence returns: now returns *jni.Object (not string) to
  prevent JNI crash on non-String CharSequence implementations
- Fix local ref leak on GlobalRef promotion in return values
- Fix local ref leak for string parameters (add deferred DeleteLocalRef)
- Remove initSkipped dead code from all init.go files

Hand-written code fixes:
- alarm/extract.go: add ShowIntent field, fix local ref leak
- location/extract.go: add Altitude/Bearing/Speed/Accuracy/Time, fix leaks
- speech/new_tts.go: fix local ref leaks
- renderText: fix GlobalRef leaks for Canvas/Paint, use local buffer for
  thread safety, fix ignored NewStringUTF errors

Author: xaionaro@dx.center