feat: Add integration test suite for v1.1.0 commands

Adds WEEVIL_HOME-based test isolation so cargo test never touches
the real system. All commands run against a fresh TempDir per test.

Environment tests cover doctor, uninstall, new, and setup across
every combination of missing/present dependencies. Project lifecycle
tests cover creation, config persistence, upgrade, and build scripts.

Full round-trip lifecycle test: new → gradlew test → gradlew
compileJava → uninstall → doctor (unhealthy) → setup → doctor
(healthy). Confirms skeleton projects build and pass tests out of
the box, and that uninstall leaves user projects untouched.

34 tests, zero warnings.

tests/integration.rs

@@ -1,8 +1,13 @@
 use assert_cmd::prelude::*;
 use predicates::prelude::*;
-use tempfile::TempDir;
 use std::process::Command;
 
+#[path = "integration/environment_tests.rs"]
+mod environment_tests;
+
+#[path = "integration/project_lifecycle_tests.rs"]
+mod project_lifecycle_tests;
+
 #[test]
 fn test_help_command() {
     let mut cmd = Command::new(assert_cmd::cargo::cargo_bin!("weevil"));
@@ -31,25 +36,4 @@ fn test_sdk_status_command() {
     cmd.assert()
         .success()
         .stdout(predicate::str::contains("SDK Configuration"));
-}
-
-// Project creation test - will need mock SDKs
-#[test]
-#[ignore] // Ignore until we have mock SDKs set up
-fn test_project_creation() {
-    let temp = TempDir::new().unwrap();
-    
-    let mut cmd = Command::new(assert_cmd::cargo::cargo_bin!("weevil"));
-    cmd.current_dir(&temp)
-        .arg("new")
-        .arg("test-robot");
-    
-    cmd.assert()
-        .success()
-        .stdout(predicate::str::contains("Project Created"));
-    
-    // Verify project structure
-    assert!(temp.path().join("test-robot/README.md").exists());
-    assert!(temp.path().join("test-robot/build.gradle.kts").exists());
-    assert!(temp.path().join("test-robot/gradlew").exists());
 }