fix: red-team findings — verify-gate identity, single quoting authority, Windows paths

Red-team pass over the hardened diff (several findings empirically verified
by the reviewer before reporting):

- KNOWN_HOOKS gains the sixth identity: gstack-verify-gate (README-documented
  opt-in Stop hook). A tag-stripped verify-gate entry previously survived
  prune-stale --all and errored at the end of EVERY turn after uninstall
  deleted the install root — the exact phantom-hook class this branch fixes.
  Uninstall also sweeps its tagged form.
- add-event is now the single quoting authority: every registered command is
  normalized through the same gsQuoteCmd/gsStripWrap round-trip the healer
  uses. Pre-fix, only SessionStart got caller-side quoting — a spaced/metachar
  canonical root registered broken plan-tune/AUQ/timeline hooks that the very
  next heal rewrote (the codebase disagreed with its own registrations).
- Windows: MSYS-form paths (/c/Users/...) are drive-translated for fs checks
  only (gsWinPath) — native bun resolved them drive-relative, so the heal
  judged every LIVE Windows hook dead and pruned it. The three AskUserQuestion
  hooks and the Stop hook now also get the mandatory 'bash ' prefix on
  Windows (previously only SessionStart did; extensionless bash shims
  otherwise hit the file-association dialog).
- CANONICAL_GSTACK_ROOT falls back to $HOME/.claude/skills/gstack when a
  CLAUDE_CONFIG_DIR-derived root was never installed (the installer hardcodes
  the home path — split-brain left such users permanently hookless).
- prune-stale preserves foreign entries that STARTED empty (they were
  silently deleted, uncounted, on every heal).
- The timeline Stop registration and its list-sources guard join the
  zero-silent-mutations contract (stderr attached).

Tests: verify-gate tag-stripped heal+sweep, started-empty preservation,
add-event quoting-authority round-trip.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

bin/gstack-settings-hook

@@ -81,7 +81,8 @@ var KNOWN_HOOKS = {
   "question-preference-hook": { source: "plan-tune-cathedral", event: "PreToolUse",   matcher: "(AskUserQuestion|mcp__.*__AskUserQuestion)", relpath: "hosts/claude/hooks/question-preference-hook" },
   "auq-error-fallback-hook":  { source: "auq-error-fallback",  event: "PostToolUse",  matcher: "(AskUserQuestion|mcp__.*__AskUserQuestion)", relpath: "hosts/claude/hooks/auq-error-fallback-hook" },
   "timeline-stop-hook":       { source: "gstack-timeline-stop", event: "Stop",        matcher: "", relpath: "hosts/claude/hooks/timeline-stop-hook" },
-  "gstack-session-update":    { source: "gstack-session-update", event: "SessionStart", matcher: "", relpath: "bin/gstack-session-update" }
+  "gstack-session-update":    { source: "gstack-session-update", event: "SessionStart", matcher: "", relpath: "bin/gstack-session-update" },
+  "gstack-verify-gate":       { source: "verify-gate", event: "Stop", matcher: "", relpath: "bin/gstack-verify-gate" }
 };
 function gsHadBashPrefix(c) { return String(c == null ? "" : c).trim().indexOf("bash ") === 0; }
 function gsStripWrap(c) {
@@ -105,9 +106,18 @@ function gsOwnedRow(cmd, event, matcher) {
   if (row.matcher && (matcher || "") !== row.matcher) return null;
   return row;
 }
+function gsWinPath(p) {
+  // Git Bash writes MSYS-form paths (/c/Users/...) into settings.json, but
+  // native bun resolves them drive-relative (C:\c\Users\...) -- translate for
+  // fs calls only; stored commands keep the form the firing shell expects.
+  if (process.platform === "win32" && /^\/[A-Za-z]\//.test(p)) {
+    return p.charAt(1) + ":" + p.slice(2);
+  }
+  return p;
+}
 function gsIsAlive(cmd) {
   var fs = require("fs");
-  var p = gsStripWrap(cmd);
+  var p = gsWinPath(gsStripWrap(cmd));
   if (!p) return false;
   try {
     if (process.platform === "win32") return fs.existsSync(p);
@@ -364,7 +374,12 @@ case "$ACTION" in
       if (!settings.hooks) settings.hooks = {};
       if (!settings.hooks[event]) settings.hooks[event] = [];
 
-      const hookEntry = { type: "command", command: cmd };
+      // add-event is the single quoting authority: normalize the command
+      // through the same round-trip the healer uses so metachar paths are
+      // registered in the escaped-quoted form from the start (a caller-side
+      // quoting step would drift per call site).
+      const cmdNorm = gsQuoteCmd(gsStripWrap(cmd), gsHadBashPrefix(cmd));
+      const hookEntry = { type: "command", command: cmdNorm };
       if (timeoutRaw) {
         const n = Number(timeoutRaw);
         if (Number.isFinite(n) && n > 0) hookEntry.timeout = n;
@@ -379,12 +394,12 @@ case "$ACTION" in
       for (const entry of settings.hooks[event]) {
         if ((entry.matcher || "") !== matcher) continue;
         if (!Array.isArray(entry.hooks)) continue;
-        let idx = entry.hooks.findIndex(h => h && h.command === cmd);
+        let idx = entry.hooks.findIndex(h => h && h.command === cmdNorm);
         if (idx < 0) {
           idx = entry.hooks.findIndex(h => {
             if (!h || !h.command) return false;
             const row = gsOwnedRow(h.command, event, entry.matcher || "");
-            return !!row && gsBaseOf(h.command) === gsBaseOf(cmd);
+            return !!row && gsBaseOf(h.command) === gsBaseOf(cmdNorm);
           });
         }
         if (idx < 0 && entry._gstack_source === source && entry.hooks.length === 1) {
@@ -542,6 +557,14 @@ case "$ACTION" in
             let removedHere = 0;
             const remain = [];
             const seenInEntry = new Set();
+            if (entry.hooks.length === 0) {
+              // Started-empty entries are foreign data we never touched --
+              // preserve them (only a gstack-tagged empty entry is claimable,
+              // and only by the --all sweep).
+              if (all && entry._gstack_source) { removed++; continue; }
+              rebuilt.push(entry);
+              continue;
+            }
             for (const h of entry.hooks) {
               const cmdRaw = h && h.command;
               const row = cmdRaw ? gsOwnedRow(cmdRaw, event, matcher) : null;

bin/gstack-uninstall

@@ -153,6 +153,10 @@ if [ -x "$SETTINGS_HOOK" ]; then
   if "$SETTINGS_HOOK" remove-source --source gstack-timeline-stop | grep -q "removed [1-9]"; then
     REMOVED+=("timeline Stop hook")
   fi
+  # Verification stop hook (opt-in via README; user-registered, ours to sweep).
+  if "$SETTINGS_HOOK" remove-source --source verify-gate | grep -q "removed [1-9]"; then
+    REMOVED+=("verification Stop hook")
+  fi
   # Identity sweep for untagged strays (Claude Code strips _gstack_source
   # tags; pre-v1.67 setups baked worktree paths). Removes every gstack-owned
   # hook item, live or dead — the binaries they point at are being deleted.

setup

@@ -1870,6 +1870,14 @@ SETTINGS_HOOK="$SOURCE_GSTACK_DIR/bin/gstack-settings-hook"
 # WARNING for future code AND migrations (the v1.58.0.0.sh defect class):
 # NEVER register ${SCRIPT_DIR}/$SOURCE_GSTACK_DIR-relative hook paths.
 CANONICAL_GSTACK_ROOT="${CLAUDE_CONFIG_DIR:-$HOME/.claude}/skills/gstack"
+# Split-brain guard: the installer currently hardcodes $HOME/.claude/skills
+# (setup:1601 TODO), so a CLAUDE_CONFIG_DIR override can name a root that was
+# never installed. Fall back to where the install actually lives — both are
+# stable, neither is the running tree, so canonical-only still holds.
+if [ ! -x "$CANONICAL_GSTACK_ROOT/bin/gstack-session-update" ] \
+   && [ -x "$HOME/.claude/skills/gstack/bin/gstack-session-update" ]; then
+  CANONICAL_GSTACK_ROOT="$HOME/.claude/skills/gstack"
+fi
 
 # Echo the canonical path for a hook (repo-relative arg); fails when the hook
 # is not executable at the canonical install — callers must skip + log.
@@ -1920,14 +1928,9 @@ fi
 SESSION_UPDATE_CMD="$(_hook_command_path bin/gstack-session-update || true)"
 HOOK_CMD=""
 if [ -n "$SESSION_UPDATE_CMD" ]; then
-  # The registered command is executed by a shell when Claude Code fires the
-  # hook — neutralize shell metacharacters, not just whitespace (mirrors
-  # gsQuoteCmd in gstack-settings-hook).
-  case "$SESSION_UPDATE_CMD" in
-    *[\ \"\$\`\\]*)
-      SESSION_UPDATE_CMD="\"$(printf '%s' "$SESSION_UPDATE_CMD" | sed 's/[\\"$`]/\\&/g')\""
-      ;;
-  esac
+  # No caller-side quoting: add-event is the single quoting authority — it
+  # normalizes every registered command through the same gsQuoteCmd round-trip
+  # the healer uses, so metachar/space paths cannot drift per call site.
   if [ "$IS_WINDOWS" -eq 1 ]; then
     HOOK_CMD="bash $SESSION_UPDATE_CMD"
   else
@@ -2073,6 +2076,14 @@ fi
 PLAN_TUNE_LOG_HOOK="$(_hook_command_path hosts/claude/hooks/question-log-hook || true)"
 PLAN_TUNE_PREF_HOOK="$(_hook_command_path hosts/claude/hooks/question-preference-hook || true)"
 AUQ_ERROR_FALLBACK_HOOK="$(_hook_command_path hosts/claude/hooks/auq-error-fallback-hook || true)"
+# Windows: extensionless bash shims need the explicit 'bash ' prefix (same
+# rationale as HOOK_CMD above — the OS file-association dialog otherwise).
+# KNOWN_HOOKS identity round-trips the prefix, so healing preserves it.
+if [ "$IS_WINDOWS" -eq 1 ]; then
+  [ -n "$PLAN_TUNE_LOG_HOOK" ] && PLAN_TUNE_LOG_HOOK="bash $PLAN_TUNE_LOG_HOOK"
+  [ -n "$PLAN_TUNE_PREF_HOOK" ] && PLAN_TUNE_PREF_HOOK="bash $PLAN_TUNE_PREF_HOOK"
+  [ -n "$AUQ_ERROR_FALLBACK_HOOK" ] && AUQ_ERROR_FALLBACK_HOOK="bash $AUQ_ERROR_FALLBACK_HOOK"
+fi
 PLAN_TUNE_INSTALL_MARKER="$HOME/.gstack/.plan-tune-hooks-prompted"
 
 # Canonical-only: an ephemeral tree with no stable install gets a visible skip,
@@ -2275,13 +2286,18 @@ fi
 # a session. Idempotent via the (event, source) dedup in gstack-settings-hook;
 # removed by --no-team and gstack-uninstall.
 TIMELINE_STOP_HOOK="$(_hook_command_path hosts/claude/hooks/timeline-stop-hook || true)"
+if [ "$IS_WINDOWS" -eq 1 ] && [ -n "$TIMELINE_STOP_HOOK" ]; then
+  TIMELINE_STOP_HOOK="bash $TIMELINE_STOP_HOOK"
+fi
+# stderr stays attached on both calls below (zero silent settings mutations;
+# the list-sources corrupt-file warning must reach the user too).
 if [ "$NO_TEAM_MODE" -ne 1 ] && [ -x "$SETTINGS_HOOK" ] && [ -n "$TIMELINE_STOP_HOOK" ]; then
-  if ! "$SETTINGS_HOOK" list-sources 2>/dev/null | grep -q "gstack-timeline-stop"; then
+  if ! "$SETTINGS_HOOK" list-sources | grep -q "gstack-timeline-stop"; then
     if "$SETTINGS_HOOK" add-event \
       --event Stop \
       --command "$TIMELINE_STOP_HOOK" \
       --source gstack-timeline-stop \
-      --timeout 5 >/dev/null 2>&1; then
+      --timeout 5 >/dev/null; then
       log "  registered Stop hook: session timeline entries now close even when a skill is interrupted (backup: settings.json.bak.<ts>; remove: $SETTINGS_HOOK remove-source --source gstack-timeline-stop)"
     fi
   fi

test/gstack-settings-hook-schema-aware.test.ts

@@ -597,6 +597,56 @@ describe('review-army hardening (specialist findings)', () => {
     expect(fs.existsSync(latest)).toBe(true);
   });
 
+  test('tag-stripped verify-gate entry is table-owned: healed by --repoint, swept by --all', () => {
+    // Red-team catch: verify-gate is a README-documented opt-in Stop hook.
+    // Without a KNOWN_HOOKS row, a tag-stripped entry survived uninstall and
+    // errored at the end of EVERY turn after the install root was deleted.
+    const canon = mkCanon(tmpDir);
+    const vg = path.join(canon, 'bin', 'gstack-verify-gate');
+    fs.writeFileSync(vg, '#!/bin/sh\n');
+    fs.chmodSync(vg, 0o755);
+    fs.writeFileSync(settingsFile, JSON.stringify({
+      hooks: { Stop: [hookEntry('/dead/install/bin/gstack-verify-gate')] },   // tag STRIPPED
+    }, null, 2));
+    runIso(['prune-stale', '--repoint', canon]);
+    let s = settings();
+    expect(s.hooks.Stop[0].hooks[0].command).toBe(vg);
+    expect(s.hooks.Stop[0]._gstack_source).toBe('verify-gate');
+    const r = runIso(['prune-stale', '--all']);
+    expect(r.stdout).toMatch(/removed 1/);
+    expect(settings().hooks).toBeUndefined();
+  });
+
+  test('a foreign entry that STARTED empty survives prune-stale untouched', () => {
+    fs.writeFileSync(settingsFile, JSON.stringify({
+      hooks: { PreToolUse: [{ matcher: 'Bash', hooks: [] }] },
+    }, null, 2) + '\n');
+    const before = fs.readFileSync(settingsFile, 'utf-8');
+    const r = runIso(['prune-stale', '--repoint', mkCanon(tmpDir, 'c2')]);
+    expect(r.stdout).toMatch(/removed 0 gstack hook entries \(repointed 0\)/);
+    expect(fs.readFileSync(settingsFile, 'utf-8')).toBe(before);
+  });
+
+  test('add-event is the quoting authority: spaced canonical path stored escaped-quoted, healer idempotent', () => {
+    // Red-team catch (empirically verified pre-fix): setup registered raw
+    // paths and the very next heal rewrote them — fresh installs shipped a
+    // form the codebase itself considered wrong.
+    const spacedBase = path.join(tmpDir, 'canon root');
+    fs.mkdirSync(spacedBase, { recursive: true });
+    const canon = mkCanon(spacedBase);
+    runIso([
+      'add-event', '--event', 'PostToolUse', '--matcher', AUQ_MATCHER,
+      '--command', `${canon}/hosts/claude/hooks/question-log-hook`,
+      '--source', 'plan-tune-cathedral', '--timeout', '5',
+    ]);
+    const stored = settings().hooks.PostToolUse[0].hooks[0].command;
+    expect(stored).toBe(`"${canon}/hosts/claude/hooks/question-log-hook"`);
+    const before = fs.readFileSync(settingsFile, 'utf-8');
+    const r = runIso(['prune-stale', '--repoint', canon]);
+    expect(r.stdout).toMatch(/removed 0 gstack hook entries \(repointed 0\)/);
+    expect(fs.readFileSync(settingsFile, 'utf-8')).toBe(before);
+  });
+
   test('rollback refuses a pointer that names a non-backup file', () => {
     fs.writeFileSync(settingsFile, JSON.stringify({ a: 1 }, null, 2));
     const evil = path.join(tmpDir, 'evil.json');