docs: add package.md as dokka api landing page

Author: rasros

build.gradle.kts

@@ -39,6 +39,7 @@ kotlin {
 
 dokka {
     dokkaSourceSets.configureEach {
+        includes.from("package.md")
         sourceLink {
             localDirectory.set(projectDir.resolve("src"))
             val sub = projectDir.relativeTo(rootDir).invariantSeparatorsPath

package.md

@@ -0,0 +1,22 @@
+# Module kencode
+
+# Package com.eignex.kencode
+
+Start here to find your way around the API. Three entry points cover the
+common tasks; everything else in the symbol list supports them.
+
+| Start with | When you want to |
+|---|---|
+| [EncodedFormat] | Turn a `@Serializable` type into a short string, and back. |
+| [PackedFormat] | Get the compact `ByteArray` without the text layer. |
+| [ByteEncoding] | Encode raw bytes with a codec directly — [Base62], [Base36], [Base64], [Base85]. |
+
+```kotlin
+val encoded = EncodedFormat.encodeToString(payload)
+val decoded = EncodedFormat.decodeFromString<Payload>(encoded)
+```
+
+Configure a format through its builder lambda: swap the [codec][EncodedFormatBuilder.codec],
+add a [checksum][EncodedFormatBuilder.checksum], or chain [PayloadTransform]s.
+On the packed side, annotate `Int`/`Long` fields with [PackedType] and
+[IntPacking] to opt into varint or ZigZag.