fix: single source of truth for version across crate and tests

Replace all hardcoded "1.1.0" version strings with env!("CARGO_PKG_VERSION")
in src/, so Cargo.toml is the sole source for the built binary. Tests
intentionally use a separate hardcoded constant in tests/common.rs to act
as a canary — they will fail on a version bump until manually updated.

- src/project/mod.rs: add WEEVIL_VERSION const, wire into Tera context,
  generated README, and .weevil-version marker
- tests/common.rs: new file, holds EXPECTED_VERSION for all test crates
- tests/{integration,project_lifecycle,unit/config_tests}.rs: pull from
  common instead of env! or inline literals

tests/unit/config_tests.rs

@@ -6,6 +6,10 @@ use std::path::PathBuf;
 use tempfile::TempDir;
 use std::fs;
 
+#[path = "../common.rs"]
+mod common;
+use common::EXPECTED_VERSION;
+
 #[test]
 fn test_config_create_and_save() {
     let temp_dir = TempDir::new().unwrap();
@@ -15,7 +19,7 @@ fn test_config_create_and_save() {
     
     assert_eq!(config.project_name, "test-robot");
     assert_eq!(config.ftc_sdk_path, sdk_path);
-    assert_eq!(config.weevil_version, "1.0.0");
+    assert_eq!(config.weevil_version, EXPECTED_VERSION);
     
     // Save and reload
     config.save(temp_dir.path()).unwrap();
@@ -45,7 +49,7 @@ fn test_config_toml_format() {
     let content = fs::read_to_string(temp_dir.path().join(".weevil.toml")).unwrap();
     
     assert!(content.contains("project_name = \"my-robot\""));
-    assert!(content.contains("weevil_version = \"1.0.0\""));
+    assert!(content.contains(&format!("weevil_version = \"{}\"", EXPECTED_VERSION)));
     assert!(content.contains("ftc_sdk_path"));
 }