fix(scope): venv, vendor/, config skills/, both config dirs, case-canonical paths

PLAN § v8.1.3 punkt 1-3, PM decisions in order 20260923T092223Z:
- punkt 1: a `site-packages` or `vendor` segment below cwd is foreign
  like `node_modules`; a config dir's `skills/` is foreign like its
  `plugins/`. Safe direction: a false foreign costs an extra finding.
- punkt 2: `~/.claude` and `$CLAUDE_CONFIG_DIR` both count; a leading
  `~` in the variable is expanded. Anthropic's docs (claude-directory,
  env-vars) do not say whether Claude Code expands it: not verified,
  so both readings are foreign.
- punkt 3: realpathSync.native canonicalizes case on a case-insensitive
  volume (measured: realpathSync keeps `sub`, .native gives `Sub`), so
  NODE_MODULES/x is foreign and a case-mismatched own path is own
  (closes § v8.1.2 punkt 4).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scanners/lib/own-working-tree.mjs

@@ -28,10 +28,22 @@
 // target under Claude Code's plugin dir — `$CLAUDE_CONFIG_DIR/plugins`, default
 // `~/.claude/plugins` (cache/ and marketplaces/). A general "no `.git` of its
 // own" rule was not taken: it would shut out ordinary subdirectories of the
-// caller's own repo. Known limits — these still count as own: a `git archive`
+// caller's own repo. Known limit in v8.1.2: other install locations still
-// export or unpacked tarball under cwd (no marker at all), and other install
+// counted as own.
-// locations this rule does not name (a Python venv's site-packages, a
+//
-// composer/bundler `vendor/` dir, skills copied into a git-tracked ~/.claude).
+// v8.1.3 (order 20260923T092223Z, PM decisions) widened both checks:
+// (1) a `site-packages` (Python venv) or `vendor` (composer/bundler/Go)
+// segment below cwd is foreign like `node_modules`, and a Claude Code config
+// dir's `skills/` is foreign like its `plugins/` (third-party skills copied
+// into a git-tracked ~/.claude share its git root); (2) the config dirs are
+// BOTH `~/.claude` and `$CLAUDE_CONFIG_DIR`, whose leading `~` is expanded
+// (Anthropic's docs do not say whether Claude Code expands it — not verified,
+// so both readings count as foreign); (3) paths are realpath'd with
+// `realpathSync.native`, which canonicalizes case on a case-insensitive
+// volume: `NODE_MODULES/x` is the `node_modules` it names, and a
+// case-mismatched path to an own dir is own. Still own (known limits): a
+// `git archive` export or unpacked tarball under cwd (no marker at all), and
+// cwd inside `node_modules` with a sibling package as target.
 
 import { resolve, sep, join, dirname, relative } from 'node:path';
 import { realpathSync, existsSync } from 'node:fs';
@@ -52,21 +64,37 @@ function gitRoot(start) {
   }
 }
 
-/**
+// Path segments below cwd that mark installed third-party code.
- * Claude Code's plugin dir: `$CLAUDE_CONFIG_DIR/plugins` (a relative value is
+const INSTALL_SEGMENTS = ['node_modules', 'site-packages', 'vendor'];
- * resolved against cwd), else `~/.claude/plugins`. Realpath'd when it exists.
+
- * @returns {string}
+// Subdirs of a Claude Code config dir that hold third-party code.
- */
+const CONFIG_INSTALL_DIRS = ['plugins', 'skills'];
-function pluginDir() {
+
-  const configDir = process.env.CLAUDE_CONFIG_DIR || join(homedir(), '.claude');
+/** Realpath with case canonicalized; the input itself when it does not exist. */
-  const dir = resolve(configDir, 'plugins');
+function realOrSelf(p) {
   try {
-    return realpathSync(dir);
+    return realpathSync.native(p);
   } catch {
-    return dir;
+    return p;
   }
 }
 
+/**
+ * Claude Code's install dirs: `plugins/` and `skills/` under `~/.claude` and,
+ * when set, under `$CLAUDE_CONFIG_DIR` (a leading `~` is expanded, a relative
+ * value is resolved against cwd).
+ * @returns {string[]}
+ */
+function configInstallDirs() {
+  const configDirs = [join(homedir(), '.claude')];
+  const env = process.env.CLAUDE_CONFIG_DIR;
+  if (env) {
+    const expanded = env === '~' || env.startsWith('~/') ? join(homedir(), env.slice(1)) : env;
+    configDirs.push(resolve(expanded));
+  }
+  return configDirs.flatMap(dir => CONFIG_INSTALL_DIRS.map(sub => realOrSelf(join(dir, sub))));
+}
+
 /**
  * @param {string} targetPath
  * @returns {boolean}
@@ -76,21 +104,21 @@ export function isOwnWorkingTree(targetPath) {
   let resolvedCwd;
   let resolvedTmp;
   try {
-    resolvedTarget = realpathSync(resolve(targetPath));
+    resolvedTarget = realpathSync.native(resolve(targetPath));
-    resolvedCwd = realpathSync(process.cwd());
+    resolvedCwd = realpathSync.native(process.cwd());
-    resolvedTmp = realpathSync(tmpdir());
+    resolvedTmp = realpathSync.native(tmpdir());
   } catch {
     return false;
   }
   if (resolvedTarget === resolvedTmp || resolvedTarget.startsWith(resolvedTmp + sep)) {
     return false;
   }
-  const plugins = pluginDir();
+  for (const dir of configInstallDirs()) {
-  if (resolvedTarget === plugins || resolvedTarget.startsWith(plugins + sep)) {
+    if (resolvedTarget === dir || resolvedTarget.startsWith(dir + sep)) return false;
-    return false;
   }
   const underCwd = resolvedTarget === resolvedCwd || resolvedTarget.startsWith(resolvedCwd + sep);
   if (!underCwd) return false;
-  if (relative(resolvedCwd, resolvedTarget).split(sep).includes('node_modules')) return false;
+  const below = relative(resolvedCwd, resolvedTarget).split(sep);
+  if (below.some(segment => INSTALL_SEGMENTS.includes(segment))) return false;
   return gitRoot(resolvedTarget) === gitRoot(resolvedCwd);
 }