fix: normalize Conda environment cache keys (Fixes #488) (#490)

## Summary

- normalize Conda environment metadata cache keys before lookup and
insertion
- use normalized keys when removing stale entries and pruning deleted
prefixes
- preserve caller-requested prefixes on cache hits
- add Windows coverage for equivalent separator styles

## Validation

- `cargo test -p pet-conda environment_info_cache_`
- `.\scripts\rust-precommit.ps1`

Fixes #488

---------

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

Author: karthiknadig

crates/pet-conda/src/lib.rs

@@ -172,24 +172,27 @@ impl Conda {
     where
         F: FnOnce() -> Option<CondaEnvironmentDetails>,
     {
+        let cache_key = norm_case(path);
         let fingerprint_before = CondaEnvironmentFingerprint::from_prefix(path);
         if let Some(fingerprint) = &fingerprint_before {
             if let Some(cached) = self
                 .environment_info_cache
                 .read()
                 .expect("conda environment info cache lock poisoned")
-                .get(path)
+                .get(&cache_key)
                 .filter(|cached| &cached.fingerprint == fingerprint)
             {
-                return Some(cached.details.clone());
+                let mut details = cached.details.clone();
+                details.environment.prefix = Some(path.to_path_buf());
+                return Some(details);
             }
         }
 
         let Some(details) = load() else {
             self.environment_info_cache
                 .write()
                 .expect("conda environment info cache lock poisoned")
-                .remove(path);
+                .remove(&cache_key);
             return None;
         };
         let fingerprint_after = CondaEnvironmentFingerprint::from_prefix(path);
@@ -199,14 +202,14 @@ impl Conda {
             .expect("conda environment info cache lock poisoned");
         if fingerprint_before.is_some() && fingerprint_before == fingerprint_after {
             cache.insert(
-                path.to_path_buf(),
+                cache_key,
                 CachedCondaEnvironment {
                     fingerprint: fingerprint_after.expect("fingerprint checked as present"),
                     details: details.clone(),
                 },
             );
         } else {
-            cache.remove(path);
+            cache.remove(&cache_key);
         }
 
         Some(details)
@@ -458,7 +461,8 @@ impl Locator for Conda {
             }
 
             let possible_conda_envs = get_conda_environment_paths(&env_vars, &executable);
-            let active_prefixes: HashSet<PathBuf> = possible_conda_envs.iter().cloned().collect();
+            let active_prefixes: HashSet<PathBuf> =
+                possible_conda_envs.iter().map(norm_case).collect();
             for path in possible_conda_envs {
                 s.spawn(move || {
                     let details = self.get_environment_details(&path)?;
@@ -594,4 +598,41 @@ mod tests {
 
         fs::remove_dir_all(prefix).unwrap();
     }
+
+    #[cfg(windows)]
+    #[test]
+    fn environment_info_cache_normalizes_windows_keys() {
+        static NEXT_ID: AtomicUsize = AtomicUsize::new(0);
+
+        let prefix = std::env::temp_dir().join(format!(
+            "pet-conda-environment-cache-case-{}-{}",
+            std::process::id(),
+            NEXT_ID.fetch_add(1, Ordering::Relaxed)
+        ));
+        let conda_meta = prefix.join("conda-meta");
+        fs::create_dir_all(&conda_meta).unwrap();
+        fs::write(conda_meta.join("history"), "history").unwrap();
+
+        let alternate_separators = PathBuf::from(prefix.to_string_lossy().replace('\\', "/"));
+        let environment = EnvironmentApi::new();
+        let locator = Conda::from(&environment);
+        let loads = AtomicUsize::new(0);
+
+        locator
+            .get_or_load_environment_details(&prefix, || {
+                loads.fetch_add(1, Ordering::Relaxed);
+                Some(test_details(&prefix, 1))
+            })
+            .unwrap();
+        let cached = locator
+            .get_or_load_environment_details(&alternate_separators, || {
+                panic!("equivalent Windows paths should reuse the cache")
+            })
+            .unwrap();
+
+        assert_eq!(loads.load(Ordering::Relaxed), 1);
+        assert_eq!(cached.environment.prefix, Some(alternate_separators));
+
+        fs::remove_dir_all(prefix).unwrap();
+    }
 }