Update Kotlin Language Server to v261.13587.0 and refactor it to use DependencyProvider (#1061)

---------

Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>
Co-authored-by: Michael Panchenko <michael.panchenko@oraios-ai.de>

docs/02-usage/050_configuration.md

@@ -210,7 +210,7 @@ ls_specific_settings:
 ```
 
 This is supported by all language servers deriving their dependency provider from  `LanguageServerDependencyProviderSinglePath`.
-Currently, this includes the following languages: `bash`, `clojure`, `cpp`, `markdown`, `php`, `php_phpactor`, `python`, `rust`, `toml`, `typescript`, `yaml`. 
+Currently, this includes the following languages: `bash`, `clojure`, `cpp`, `kotlin`, `markdown`, `php`, `php_phpactor`, `python`, `rust`, `toml`, `typescript`, `yaml`.
 We will add support for more languages over time.
 
 #### C# (Roslyn Language Server)
@@ -281,6 +281,25 @@ Notes:
 - `GOFLAGS` (from the environment you start Serena in) may also affect the Go build context. Prefer `buildFlags` for tags.
 - Build context changes are only picked up when `gopls` starts. After changing `gopls_settings` (or relevant env vars like `GOFLAGS`), restart the Serena process (or server) that hosts the Go language server, or use your client's "Restart language server" action if it causes `gopls` to restart.
 
+#### Kotlin
+
+Serena uses [JetBrains' Kotlin Language Server](https://github.com/Kotlin/kotlin-lsp) for Kotlin support.
+
+**Runtime Requirements:**
+
+- Java 21 or higher is required. If not found, Serena automatically downloads an appropriate JRE.
+- The Kotlin Language Server is automatically downloaded from JetBrains' CDN.
+
+**Configuration:**
+
+```yaml
+ls_specific_settings:
+  kotlin:
+    ls_path: "/path/to/kotlin-lsp.sh"        # Override the Kotlin Language Server executable
+    kotlin_lsp_version: "261.13587.0"         # Override the Kotlin Language Server version
+    jvm_options: "-Xmx4G -XX:+UseG1GC"       # JVM options (default: -Xmx2G). Set to "" to disable.
+```
+
 #### Pascal (`pasls`)
 
 Serena uses [pasls](https://github.com/genericptr/pascal-language-server) (Pascal Language Server) for Pascal/Free Pascal support.