Preserve failing search candidate diagnostics

docs/roadmap/remediation.md

@@ -1,6 +1,6 @@
 # Configuration Discovery Review Findings
 
-Status: finding 1 complete; findings 2–5 remain open.
+Status: findings 1–2 complete; findings 3–5 remain open.
 
 Reviewed commit: `e50fee2`, including the discovery implementation commits after
 `424c897`. The review compared the implementation with the
@@ -53,7 +53,14 @@ or require callers to omit an otherwise valid options value.
 
 ## 2. Preserve The Failing Candidate's Identity In Access Diagnostics
 
-Priority: P2. Status: open.
+Priority: P2. Status: complete.
+
+**Completed:** terminal probe failures retain the candidate descriptor and gain
+normal file-source evidence at the acquisition boundary. Regression tests compare
+ordinary and later-underlay failures with explicit-file errors, including source
+IDs, placement, layers, and skipped missing candidates. A controlled permission
+probe checks the diagnostic-to-file link. The load regression failed before the
+fix; focused discovery/failure tests and `./scripts/check.sh` passed on Linux.
 
 **Location:** [discovery.go](../../internal/engine/discovery.go), lines 517–528,
 and the early resolver-error return in