fix(#3663): fold path casing only on win32 in the w027 active-worktree check (#3793)

* test(#3663): failing-first rows for w027 path-casing normalization

* fix(#3663): fold path casing only on win32 in the w027 active-worktree check

* fix(#3663): close review findings — seam-owned compare key, deterministic case pin

* chore(#3663): backfill changeset pr number

---------

Co-authored-by: sim <sim@local>

src/health-diagnostic-rules/worktree-health.cts

@@ -35,7 +35,8 @@
  * gsd-core/bin/lib/health-diagnostic-rules/worktree-health.cjs (gitignored).
  */
 
-import path from 'node:path';
+// eslint-disable-next-line @typescript-eslint/no-require-imports
+import shellCmdProjection = require('../shell-command-projection.cjs');
 
 // eslint-disable-next-line @typescript-eslint/no-require-imports -- type-only; erased at compile time, no runtime require emitted
 import type planningSnapshotMod = require('../planning-snapshot.cjs');
@@ -141,15 +142,35 @@ function checkW017(snapshot: PlanningSnapshot): Diagnostic[] {
 // (with the real path) lives in `message`; `remedy.args.command` stays a
 // static `<path>` template, mirroring the split the brief specifies.
 
+// ─── #3663 — path-comparison provenance helper ─────────────────────────────
+//
+// snapshot.cwd is raw process-cwd-derived — path.resolve() normalizes
+// separators and relative segments but NOT casing, and a process launched via
+// a differently-cased path echoes that spelling back. finding.path is
+// `git worktree list`-derived, which self-normalizes to the canonical
+// on-disk casing (forward slashes). Comparing those two spellings strictly
+// misclassifies the ACTIVE worktree as stale on win32 — so the comparison
+// folds case ONLY on win32 (case-insensitive filesystem, via the Shell
+// Command Projection seam's toComparablePathKey — the platform-conditional
+// fold policy lives there, not per call site) and stays case-sensitive on
+// POSIX, where differently-cased paths are genuinely different directories.
+// No realpath resolution — that would change symlink matching behavior.
+function isActiveWorktreePath(
+  activeCwd: string,
+  worktreePath: string,
+  platform: string = process.platform,
+): boolean {
+  const active = shellCmdProjection.toComparablePathKey(activeCwd, platform);
+  const worktree = shellCmdProjection.toComparablePathKey(worktreePath, platform);
+  return active === worktree || active.startsWith(worktree + '/');
+}
+
 function checkW027(snapshot: PlanningSnapshot): Diagnostic[] {
   const diagnostics: Diagnostic[] = [];
   const activeCwd = snapshot.cwd;
   for (const finding of snapshot.worktreeHealth.value) {
     if (finding.kind !== 'stale') continue;
-    const normalizedWorktree = path.resolve(finding.path);
-    const isActiveWorktree =
-      activeCwd === normalizedWorktree || activeCwd.startsWith(normalizedWorktree + path.sep);
-    if (isActiveWorktree) continue;
+    if (isActiveWorktreePath(activeCwd, finding.path)) continue;
     diagnostics.push({
       code: 'W027',
       severity: SEVERITY.WARNING,
@@ -194,4 +215,4 @@ const RULES: Rule[] = [
   },
 ];
 
-export = { RULES };
+export = { RULES, isActiveWorktreePath };

src/shell-command-projection.cts

@@ -56,6 +56,21 @@ export function posixNormalize(p: string): string {
   return p.replace(/\\/g, '/');
 }
 
+/**
+ * #3663 — comparison key for a path that must equal another path regardless
+ * of spelling: separator form (forward slashes via posixNormalize), relative
+ * segments and trailing separators (path.resolve + strip), and — ONLY on
+ * win32's case-insensitive filesystem — letter casing. POSIX stays
+ * case-sensitive: differently-cased paths are genuinely different
+ * directories there. This module owns the platform-conditional fold so the
+ * policy lives at the seam instead of accreting per-call-site copies (the
+ * class init.cts's normalizeForCompare/toComparableRaw predate).
+ */
+export function toComparablePathKey(p: string, platform: string = process.platform): string {
+  const normalized = posixNormalize(path.resolve(p)).replace(/\/+$/g, '');
+  return platform === 'win32' ? normalized.toLowerCase() : normalized;
+}
+
 /**
  * Return true when a managed hook command must be prefixed with PowerShell's
  * call operator so a quoted executable token is invokable by the target