docs: keep encoding fix notes out of public README

Restore README.md to the PR base without changing the source-encoding fix or regression tests. Keep contributor-facing verification and implementation rationale in the PR description because there is no suitable existing contributor guide.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: chagong

README.md

@@ -15,12 +15,6 @@ The Java Debug Server is an implementation of Visual Studio Code (VSCode) Debug
 - Threads
 - Debug console
 
-### Source encodings
-
-File-backed source resolution, including line breakpoints, uses the workspace resource's
-encoding when available. External source files recognize UTF-8 and UTF-16 LE/BE byte
-order marks; without a byte order mark, they use the language-server JVM's default charset.
-
 ## Background
 
 The Java Debug Server is the bridge between VSCode and JVM. The implementation is based on JDI ([Java Debug Interface](https://docs.oracle.com/javase/7/docs/jdk/api/jpda/jdi/)). It works with [Eclipse JDT Language Server](https://github.com/vscjavaci/eclipse.jdt.ls) as an add-on to provide debug functionalities.
@@ -32,9 +26,6 @@ The Java Debug Server is the bridge between VSCode and JVM. The implementation i
 
 ## Installation
 
-Builds require JDK 21 or newer. `./mvnw clean verify` runs the core tests and
-the headless Eclipse/JDT plugin regression tests.
-
 ### Windows:
 ```
 mvnw.cmd clean install