Improve type safety and refactor dict entry handling

- Replace `struct dictEntry` with `typedef _dictEntryNormal`
- Rename `embeddedDictEntry` to `_dictEntryEmbedded`
- Rename `dictEntryNoValue` to `_dictEntryNoValue`
- Introduce macros for setting and getting values in dict entries
- Update functions to utilize new typedef structures and macros
- Refactor code for improved readability and maintainability

Signed-off-by: Ping Xie <[email protected]>