fix(bugs): resolve issues #2388, #2431, #2396, #2376 (#2467)

#2388 (plan-phase silently renames feature branch): add explicit Git
Branch Invariant section to plan-phase.md prohibiting branch
creation/rename/switch during planning; phase slug changes are
plan-level only and must not affect the git branch.

#2431 (worktree teardown silently swallows errors): replace
`git worktree remove --force 2>/dev/null || true` with a lock-aware
block in quick.md and execute-phase.md that detects locked worktrees,
attempts unlock+retry, and surfaces a user-visible recovery message
when removal still fails.

#2396 (hardcoded test commands bypass Makefile): add a three-tier
test command resolver (project config → Makefile/Justfile → language
sniff) in execute-phase.md, verify-phase.md, and audit-fix.md.
Makefile with a `test:` target now takes priority over npm/cargo/go.

#2376 (OpenCode @$HOME not mapped on Windows): add platform guard in
bin/install.js so OpenCode on win32 uses the absolute path instead of
`$HOME/...`, which OpenCode does not expand in @file references on
Windows.

Tests: 29 new assertions across 4 regression test files (all passing).

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/bug-2376-opencode-windows-home-path.test.cjs

@@ -0,0 +1,118 @@
+/**
+ * Regression test for #2376: @$HOME not correctly mapped in OpenCode on Windows.
+ *
+ * On Windows, $HOME is not expanded by PowerShell/cmd.exe, so OpenCode cannot
+ * resolve @$HOME/... file references in installed command files.
+ *
+ * Fix: install.js must use the absolute path (not $HOME-relative) when installing
+ * for OpenCode on Windows.
+ */
+
+'use strict';
+
+const { describe, test } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('fs');
+const path = require('path');
+
+const INSTALL_JS_PATH = path.join(__dirname, '..', 'bin', 'install.js');
+
+describe('bug-2376: OpenCode on Windows must use absolute path, not $HOME', () => {
+  test('install.js exists', () => {
+    assert.ok(fs.existsSync(INSTALL_JS_PATH), 'bin/install.js should exist');
+  });
+
+  test('install.js pathPrefix computation skips $HOME for OpenCode on Windows', () => {
+    const content = fs.readFileSync(INSTALL_JS_PATH, 'utf-8');
+
+    // The fix must include a Windows detection condition for OpenCode
+    const hasWindowsOpenCodeGuard = (
+      content.includes('isWindowsHost') ||
+      (content.includes("'win32'") && content.includes('isOpencode') && content.includes('pathPrefix'))
+    );
+    assert.ok(
+      hasWindowsOpenCodeGuard,
+      'install.js must include a Windows platform guard for OpenCode pathPrefix computation'
+    );
+  });
+
+  test('install.js pathPrefix guard excludes $HOME for OpenCode+Windows combination', () => {
+    const content = fs.readFileSync(INSTALL_JS_PATH, 'utf-8');
+
+    // The pathPrefix assignment must include a guard that prevents $HOME substitution
+    // for OpenCode on Windows (process.platform === 'win32').
+    const pathPrefixBlock = content.match(/const pathPrefix[\s\S]{0,500}resolvedTarget/);
+    assert.ok(pathPrefixBlock, 'pathPrefix assignment block should be present');
+
+    const block = pathPrefixBlock[0];
+    const excludesOpenCodeWindows = (
+      block.includes('isWindowsHost') ||
+      (block.includes('isOpencode') && block.includes('win32'))
+    );
+    assert.ok(
+      excludesOpenCodeWindows,
+      'pathPrefix computation must exclude $HOME substitution for OpenCode on Windows'
+    );
+  });
+
+  test('pathPrefix simulation: OpenCode on Windows uses absolute path', () => {
+    // Simulate the fixed pathPrefix computation for Windows+OpenCode
+    const isGlobal = true;
+    const isOpencode = true;
+    const isWindowsHost = true; // simulated Windows
+    const resolvedTarget = 'C:/Users/user/.config/opencode';
+    const homeDir = 'C:/Users/user';
+
+    const pathPrefix = isGlobal && resolvedTarget.startsWith(homeDir) && !(isOpencode && isWindowsHost)
+      ? '$HOME' + resolvedTarget.slice(homeDir.length) + '/'
+      : `${resolvedTarget}/`;
+
+    assert.strictEqual(
+      pathPrefix,
+      'C:/Users/user/.config/opencode/',
+      'OpenCode on Windows should use absolute path, not $HOME-relative'
+    );
+    assert.ok(
+      !pathPrefix.includes('$HOME'),
+      'OpenCode on Windows pathPrefix must not contain $HOME'
+    );
+  });
+
+  test('pathPrefix simulation: OpenCode on Linux/macOS still uses $HOME', () => {
+    // Non-Windows OpenCode should still use $HOME (POSIX shells expand it)
+    const isGlobal = true;
+    const isOpencode = true;
+    const isWindowsHost = false; // simulated Linux/macOS
+    const homeDir = '/home/user';
+    const resolvedTarget = '/home/user/.config/opencode';
+
+    const pathPrefix = isGlobal && resolvedTarget.startsWith(homeDir) && !(isOpencode && isWindowsHost)
+      ? '$HOME' + resolvedTarget.slice(homeDir.length) + '/'
+      : `${resolvedTarget}/`;
+
+    assert.strictEqual(
+      pathPrefix,
+      '$HOME/.config/opencode/',
+      'OpenCode on Linux/macOS should still use $HOME-relative path'
+    );
+  });
+
+  test('pathPrefix simulation: Claude Code on Windows still uses $HOME (unaffected)', () => {
+    // Claude Code on Windows is handled by Claude Code's own shell, which expands $HOME
+    const isGlobal = true;
+    const isOpencode = false; // Claude Code, not OpenCode
+    const isWindowsHost = true;
+    const homeDir = 'C:/Users/user';
+    const resolvedTarget = 'C:/Users/user/.claude';
+
+    const pathPrefix = isGlobal && resolvedTarget.startsWith(homeDir) && !(isOpencode && isWindowsHost)
+      ? '$HOME' + resolvedTarget.slice(homeDir.length) + '/'
+      : `${resolvedTarget}/`;
+
+    assert.strictEqual(
+      pathPrefix,
+      '$HOME/.claude/',
+      'Claude Code on Windows should still use $HOME-relative path (Claude Code handles this)'
+    );
+  });
+});