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/src/test/java/com/example/orders/OrderBookTest.java

@@ -0,0 +1,29 @@
+package com.example.orders;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.EnabledIfSystemProperty;
+
+class OrderBookTest {
+    @Test
+    void sumsRevenueOverAllOrders() {
+        OrderBook book = new OrderBook();
+        book.place("alice", "Keyboard", 2, 1000);
+        book.place("bob", "Mouse", 1, 500);
+        assertEquals(2500, book.revenueCents());
+        assertEquals(1, book.byCustomer("bob").size());
+    }
+
+    @Test
+    void rejectsEmptyOrders() {
+        assertThrows(IllegalArgumentException.class, () -> new Order("alice", "Keyboard", 0, 1000));
+    }
+
+    @Test
+    @EnabledIfSystemProperty(named = "openidea.fail", matches = "true")
+    void intentionallyFails() {
+        assertEquals(1, new OrderBook().size(), "QA: an intentionally failing test");
+    }
+}