Document @KeyValue and @Read list support in README

[Copilot]

The @KeyValue annotation and @Read list return types were undocumented in the README.

Changes

Added "Additional Features" section to README documenting:

• @keyvalue annotation: For reading key-value structured sheets where data is organized as two columns (key, value). The annotation transforms vertical key-value pairs into horizontal row format for data class mapping.

• @READ list support: Clarifies that @Read returns either single objects or List<T> based on return type and query, with examples of both patterns.

Example

// Key-value sheet reading
interface ConfigApi {
    @KeyValue
    @Read("SELECT *")
    @GET("config")
    suspend fun getConfig(): Config  // Maps key-value pairs to object
}

// List vs single object
interface NotesApi {
    @Read("SELECT * WHERE id = :id")
    @GET("notes")
    suspend fun getNoteById(@Query("id") id: String): Note  // Single result
    
    @Read("SELECT * ORDER BY created_at DESC LIMIT 10")
    @GET("notes")
    suspend fun getRecentNotes(): List<Note>  // Multiple results
}

Original prompt

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This section details on the original issue you should resolve

<issue_title>Update README</issue_title>
<issue_description>- Add @KeyValue and @ReadAsList annotations to README</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Update README #8

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