test(lsp): smoke-test everyday code intelligence per language with real servers (#1299)

* test(lsp): smoke-test everyday code intelligence per language with real servers

A new ide-host integration test drives completion, go to definition, Find
Usages, hover, diagnostics with a quick fix, an intention, formatting and
rename on each language's fixtures/ project, through the ops the app's
commands call and the language server the app starts by default:
TypeScript (vtsls), Python (basedpyright + Ruff), Rust (rust-analyzer),
Go (gopls), Java (jdtls) and Kotlin (kotlin-lsp). A failure names the
language and the operation.

The tests are ignored by default; a Language smoke workflow installs pinned
server versions and runs one language per job on changes to crates/,
languages/ and fixtures/. Adds fixtures/java-app (Maven, JDK 21) for Java.

* test(lsp): rename TypeScript from a usage and check Rust errors while typing

Covers the fixes the smoke test turned up: a TypeScript rename started at a
call site in another file renames the declaration (#1301), and rust-analyzer's
own diagnostics and fixes arrive without saving (#1306).

fixtures/java-app/pom.xml

@@ -0,0 +1,50 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>com.example</groupId>
+  <artifactId>openidea-fixture-orders</artifactId>
+  <version>0.1.0</version>
+  <description>OpenIDEA QA fixture: a tiny order book</description>
+
+  <properties>
+    <maven.compiler.release>21</maven.compiler.release>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <!-- `mvn test -DopenideaFail=true` runs the intentionally failing test. -->
+    <openideaFail>false</openideaFail>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter</artifactId>
+      <version>5.11.3</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>3.5.2</version>
+        <configuration>
+          <systemPropertyVariables>
+            <openidea.fail>${openideaFail}</openidea.fail>
+          </systemPropertyVariables>
+        </configuration>
+      </plugin>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>exec-maven-plugin</artifactId>
+        <version>3.5.0</version>
+        <configuration>
+          <mainClass>com.example.orders.App</mainClass>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>