feat(setup): wire --host cursor through the full install path

'./setup --host cursor' was accepted by the flag parser and then did
nothing: no INSTALL_CURSOR branch existed, so the script built binaries,
printed no 'ready' line, and installed zero skills — Cursor users had no
way to install gstack at all.

Full install slice, re-derived from PR #2547 by @szsunyuan onto the
current installers: generate .cursor/ skill docs (host config already
existed), create a minimal ~/.cursor/skills/gstack runtime root (root
SKILL.md + bin/lib/browse assets + review checklist pair + ETHOS.md +
supabase config — bin and lib travel together because bin scripts import
../lib), link the generated gstack-* skills, and plant the repo-local
.cursor/skills/gstack sidecar WITHOUT ever wiping the generated SKILL.md
files it shares a directory with (link-before-sidecar ordering keeps the
generation fallback alive). Auto mode detects Cursor via the cursor
binary or the ~/.cursor footprint. gstack-uninstall removes
~/.cursor/skills/gstack* and per-project .cursor/skills/gstack* — and
never rmdir's .cursor itself, where Cursor stores user rules.

Re-derivation deltas from the PR: the link guards carry the #2444
IS_WINDOWS bypass (re-runs refresh real-dir copies), lib/ and
supabase/config.sh ride along like every other runtime root, and the
hosts/cursor.ts sidecar field is omitted (HostConfig no longer carries
one — sidecar behavior lives in setup).

Fixes #1358

Co-authored-by: Yuan Sun <forrest.sun527@gmail.com>
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

test/uninstall.test.ts

@@ -161,5 +161,38 @@ describe('gstack-uninstall', () => {
       // Non-gstack should survive
       expect(fs.existsSync(path.join(mockHome, '.claude', 'skills', 'other-tool'))).toBe(true);
     });
+
+    test('--force removes Cursor gstack skills and leaves other Cursor skills', () => {
+      fs.mkdirSync(path.join(mockHome, '.cursor', 'skills', 'gstack'), { recursive: true });
+      fs.writeFileSync(path.join(mockHome, '.cursor', 'skills', 'gstack', 'SKILL.md'), 'test');
+      fs.mkdirSync(path.join(mockHome, '.cursor', 'skills', 'gstack-review'), { recursive: true });
+      fs.writeFileSync(path.join(mockHome, '.cursor', 'skills', 'gstack-review', 'SKILL.md'), 'test');
+      fs.mkdirSync(path.join(mockHome, '.cursor', 'skills', 'frontend-design'), { recursive: true });
+      fs.writeFileSync(path.join(mockHome, '.cursor', 'skills', 'frontend-design', 'SKILL.md'), 'keep');
+
+      fs.mkdirSync(path.join(mockGitRoot, '.cursor', 'skills', 'gstack-ship'), { recursive: true });
+      fs.writeFileSync(path.join(mockGitRoot, '.cursor', 'skills', 'gstack-ship', 'SKILL.md'), 'test');
+      fs.mkdirSync(path.join(mockGitRoot, '.cursor', 'rules'), { recursive: true });
+      fs.writeFileSync(path.join(mockGitRoot, '.cursor', 'rules', 'keep.md'), 'keep');
+
+      const result = spawnSync('bash', [UNINSTALL, '--force'], {
+        stdio: 'pipe',
+        env: {
+          ...process.env,
+          HOME: mockHome,
+          GSTACK_DIR: path.join(mockHome, '.claude', 'skills', 'gstack'),
+          GSTACK_STATE_DIR: path.join(mockHome, '.gstack'),
+        },
+        cwd: mockGitRoot,
+      });
+
+      expect(result.status).toBe(0);
+
+      expect(fs.existsSync(path.join(mockHome, '.cursor', 'skills', 'gstack'))).toBe(false);
+      expect(fs.existsSync(path.join(mockHome, '.cursor', 'skills', 'gstack-review'))).toBe(false);
+      expect(fs.existsSync(path.join(mockHome, '.cursor', 'skills', 'frontend-design'))).toBe(true);
+      expect(fs.existsSync(path.join(mockGitRoot, '.cursor', 'skills', 'gstack-ship'))).toBe(false);
+      expect(fs.existsSync(path.join(mockGitRoot, '.cursor', 'rules', 'keep.md'))).toBe(true);
+    });
   });
 });