feat: complete non-copilot instruction file detection

The 'Missed Potential' feature detects repos where users have instruction
files for other AI tools (Cursor, Windsurf, Claude, etc.) but NO Copilot
customization files — indicating Copilot may be under-configured compared
to competing tools.

Backend logic (detectMissedPotential), data types (MissedPotentialWorkspace)
and webview rendering (renderMissedPotential) were already in place.
This commit completes the feature by:

**Bug fix:**
- claude-code pattern was using CLAUDE.md as the detection signal.
  Per spec, CLAUDE.md is Copilot-compatible and must NOT trigger
  'missed potential'. Changed to .claude/settings.json instead.

**8 new patterns added to customizationPatterns.json:**
- cursor-dotrules:   .cursorrules (legacy Cursor flat rules file)
- windsurf-dotrules: .windsurfrules (legacy Windsurf flat rules file)
- windsurf-skills:   .windsurf/skills/*.md (Windsurf skill files)
- roo-code:          .roo/rules/*.md (Roo Code rules)
- opencode-config:   opencode.json (OpenCode configuration)
- trae-rules:        .trae/rules/*.md (Trae AI rules)
- junie-guidelines:  .junie/guidelines.md (JetBrains Junie)
- codex-md:          CODEX.md (OpenAI Codex instructions)

Total: 30 patterns (7 copilot + 23 non-copilot)

**Tests (9 new):**
- scanWorkspaceCustomizationFiles: category detection for copilot,
  non-copilot, .cursorrules, .claude/settings.json, opencode.json
- Verifies CLAUDE.md is NOT flagged as non-copilot
- All 87 unit tests pass

Author: rajbos

vscode-extension/src/customizationPatterns.json

@@ -2,7 +2,17 @@
   "description": "Defines Copilot customization file patterns to scan in workspaces",
   "lastUpdated": "2026-02-11",
   "stalenessThresholdDays": 90,
-  "excludeDirs": ["node_modules", ".git", "dist", "build", "out", "__pycache__", ".venv", ".next", "coverage"],
+  "excludeDirs": [
+    "node_modules",
+    ".git",
+    "dist",
+    "build",
+    "out",
+    "__pycache__",
+    ".venv",
+    ".next",
+    "coverage"
+  ],
   "patterns": [
     {
       "id": "copilot-instructions",
@@ -83,11 +93,11 @@
     },
     {
       "id": "claude-code",
-      "type": "non-copilot-instructions",
+      "type": "non-copilot-config",
       "category": "non-copilot",
       "icon": "🎭",
-      "label": "Claude Code",
-      "path": "CLAUDE.md",
+      "label": "Claude Code Settings",
+      "path": ".claude/settings.json",
       "scanMode": "exact",
       "caseInsensitive": true
     },
@@ -216,6 +226,81 @@
       "path": ".aiassistant/rules/*.md",
       "scanMode": "recursive",
       "maxDepth": 2
+    },
+    {
+      "id": "cursor-dotrules",
+      "path": ".cursorrules",
+      "scanMode": "exact",
+      "type": "non-copilot-instructions",
+      "icon": "🔷",
+      "label": "Cursor Rules (.cursorrules)",
+      "category": "non-copilot"
+    },
+    {
+      "id": "windsurf-dotrules",
+      "path": ".windsurfrules",
+      "scanMode": "exact",
+      "type": "non-copilot-instructions",
+      "icon": "🌊",
+      "label": "Windsurf Rules (.windsurfrules)",
+      "category": "non-copilot"
+    },
+    {
+      "id": "windsurf-skills",
+      "path": ".windsurf/skills/*.md",
+      "scanMode": "recursive",
+      "maxDepth": 2,
+      "type": "non-copilot-instructions",
+      "icon": "🌊",
+      "label": "Windsurf Skills",
+      "category": "non-copilot"
+    },
+    {
+      "id": "roo-code",
+      "path": ".roo/rules/*.md",
+      "scanMode": "recursive",
+      "maxDepth": 2,
+      "type": "non-copilot-instructions",
+      "icon": "🦘",
+      "label": "Roo Code Rules",
+      "category": "non-copilot"
+    },
+    {
+      "id": "opencode-config",
+      "path": "opencode.json",
+      "scanMode": "exact",
+      "type": "non-copilot-config",
+      "icon": "🔓",
+      "label": "OpenCode Config",
+      "category": "non-copilot"
+    },
+    {
+      "id": "trae-rules",
+      "path": ".trae/rules/*.md",
+      "scanMode": "recursive",
+      "maxDepth": 2,
+      "type": "non-copilot-instructions",
+      "icon": "🔧",
+      "label": "Trae Rules",
+      "category": "non-copilot"
+    },
+    {
+      "id": "junie-guidelines",
+      "path": ".junie/guidelines.md",
+      "scanMode": "exact",
+      "type": "non-copilot-instructions",
+      "icon": "🧠",
+      "label": "JetBrains Junie Guidelines",
+      "category": "non-copilot"
+    },
+    {
+      "id": "codex-md",
+      "path": "CODEX.md",
+      "scanMode": "exact",
+      "type": "non-copilot-instructions",
+      "icon": "🤖",
+      "label": "OpenAI Codex Instructions",
+      "category": "non-copilot"
     }
   ]
-}
+}

vscode-extension/test/unit/workspaceHelpers.test.ts

@@ -487,4 +487,77 @@ test('extractMcpServerName: mcp__server__tool format extracts server name', () =
 
 test('extractMcpServerName: mcp__server__multi__part__tool extracts only first server segment', () => {
         assert.equal(extractMcpServerName('mcp__my_server__tool__with__parts'), 'my_server');
-});
+});
+// ── scanWorkspaceCustomizationFiles — category detection ─────────────────
+
+import * as fs from 'node:fs';
+import * as os from 'node:os';
+import * as nodePath from 'node:path';
+import { scanWorkspaceCustomizationFiles } from '../../src/workspaceHelpers';
+
+test('scanWorkspaceCustomizationFiles: returns empty array for non-existent dir', () => {
+const result = scanWorkspaceCustomizationFiles('/does/not/exist/xyz123');
+assert.deepEqual(result, []);
+});
+
+test('scanWorkspaceCustomizationFiles: detects copilot-instructions.md as copilot category', () => {
+const tmpDir = fs.mkdtempSync(nodePath.join(os.tmpdir(), 'wh-test-'));
+try {
+const githubDir = nodePath.join(tmpDir, '.github');
+fs.mkdirSync(githubDir);
+fs.writeFileSync(nodePath.join(githubDir, 'copilot-instructions.md'), '# Instructions');
+const result = scanWorkspaceCustomizationFiles(tmpDir);
+const copilotFile = result.find(f => f.type !== 'unknown' && f.path.includes('copilot-instructions.md'));
+assert.ok(copilotFile, 'should find copilot-instructions.md');
+assert.equal(copilotFile?.category, 'copilot');
+} finally {
+fs.rmSync(tmpDir, { recursive: true, force: true });
+}
+});
+
+test('scanWorkspaceCustomizationFiles: detects .cursorrules as non-copilot category', () => {
+const tmpDir = fs.mkdtempSync(nodePath.join(os.tmpdir(), 'wh-test-'));
+try {
+fs.writeFileSync(nodePath.join(tmpDir, '.cursorrules'), '# Cursor rules');
+const result = scanWorkspaceCustomizationFiles(tmpDir);
+const cursorFile = result.find(f => f.path.includes('.cursorrules'));
+assert.ok(cursorFile, 'should find .cursorrules');
+assert.equal(cursorFile?.category, 'non-copilot');
+} finally {
+fs.rmSync(tmpDir, { recursive: true, force: true });
+}
+});
+
+test('scanWorkspaceCustomizationFiles: detects .claude/settings.json as non-copilot (not CLAUDE.md)', () => {
+const tmpDir = fs.mkdtempSync(nodePath.join(os.tmpdir(), 'wh-test-'));
+try {
+// CLAUDE.md should NOT appear as non-copilot (it is Copilot-compatible)
+fs.writeFileSync(nodePath.join(tmpDir, 'CLAUDE.md'), '# Claude instructions');
+const result = scanWorkspaceCustomizationFiles(tmpDir);
+const claudeMd = result.find(f => f.path.includes('CLAUDE.md') && f.category === 'non-copilot');
+assert.equal(claudeMd, undefined, 'CLAUDE.md should not be flagged as non-copilot');
+
+// .claude/settings.json SHOULD appear as non-copilot
+const claudeDir = nodePath.join(tmpDir, '.claude');
+fs.mkdirSync(claudeDir);
+fs.writeFileSync(nodePath.join(claudeDir, 'settings.json'), '{}');
+const result2 = scanWorkspaceCustomizationFiles(tmpDir);
+const claudeSettings = result2.find(f => f.path.includes('settings.json') && f.category === 'non-copilot');
+assert.ok(claudeSettings, 'should find .claude/settings.json as non-copilot');
+} finally {
+fs.rmSync(tmpDir, { recursive: true, force: true });
+}
+});
+
+test('scanWorkspaceCustomizationFiles: detects opencode.json as non-copilot', () => {
+const tmpDir = fs.mkdtempSync(nodePath.join(os.tmpdir(), 'wh-test-'));
+try {
+fs.writeFileSync(nodePath.join(tmpDir, 'opencode.json'), '{}');
+const result = scanWorkspaceCustomizationFiles(tmpDir);
+const opencodeFile = result.find(f => f.path.includes('opencode.json'));
+assert.ok(opencodeFile, 'should find opencode.json');
+assert.equal(opencodeFile?.category, 'non-copilot');
+} finally {
+fs.rmSync(tmpDir, { recursive: true, force: true });
+}
+});