test(chaos): fix NTFS volume probe so Windows hazard scenarios run (#68)

The chaos harness's NTFS-volume capability probe read the drive letter
from the first character of a **relative** fixture path
(`target/chaos-fixtures` -> `t` -> a nonexistent `T:\`), so
`cap:ntfs_volume` was never detected and **every NTFS hazard scenario
silently skipped on Windows and in CI** -- the `chaos hermetic` / `chaos
fake-drive (windows-latest)` jobs were green while exercising none of
them.

**Fix:** resolve the fixture root to an absolute path so the probe reads
the real drive letter (`C:`).

**Verified locally:** `run-all` goes from 61 -> 74 scenarios actually
executed (ADS, junctions, reparse points, recursive junction cycles,
sparse/compressed/EFS files, hardlinks, reserved/surrogate names), 0
real failures. Surfaced while running the #23 crypto/restore soak
natively on Windows.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: pmaxhogan

crates/driven-chaos/src/capabilities.rs

@@ -208,7 +208,14 @@ impl CapabilitySet {
 /// best-effort so the probes have an existing path to stat, and falls back to
 /// the temp dir when it cannot be created (for example, a read-only checkout).
 fn fixture_root_dir() -> std::path::PathBuf {
-    let root = std::path::PathBuf::from("target/chaos-fixtures");
+    // Absolute, so the Windows volume/NTFS probe can read the real drive letter
+    // from the path's first component. A relative "target/chaos-fixtures"
+    // mis-parses the leading 't' as the drive letter (probing a nonexistent
+    // `T:\`), so `cap:ntfs_volume` was never detected and every NTFS scenario
+    // silently skipped on Windows (and in CI).
+    let root = std::env::current_dir()
+        .map(|d| d.join("target/chaos-fixtures"))
+        .unwrap_or_else(|_| std::path::PathBuf::from("target/chaos-fixtures"));
     match std::fs::create_dir_all(&root) {
         Ok(()) => root,
         Err(_) => std::env::temp_dir(),