fix(ck): address Greptile + CodeRabbit review bugs

- Fix read-after-write in session-start.mjs: read prevSession BEFORE
  overwriting current-session.json so unsaved-session detection fires
- Fix shell injection in resume.mjs: replace execSync shell string with
  fs.existsSync for directory existence check
- Fix shell injection in shared.mjs gitSummary: replace nested \$(git ...)
  subshell with a separate runGit() call to get rev count
- Fix displayName never shown: render functions now use ctx.displayName
  ?? ctx.name so user-supplied names show instead of the slug
- Fix renderListTable: uses context.displayName ?? entry.name
- Fix init.mjs: use path.basename() instead of cwd.split('/').pop()
- Fix save.mjs confirmation: show original name, not contextDir slug

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

skills/ck/commands/init.mjs

@@ -9,7 +9,7 @@
  */
 
 import { readFileSync, existsSync } from 'fs';
-import { resolve } from 'path';
+import { resolve, basename } from 'path';
 import { readProjects } from './shared.mjs';
 
 const cwd = process.env.PWD || process.cwd();
@@ -137,7 +137,7 @@ if (readme && !output.description) {
 
 // ── Name fallback: directory name ─────────────────────────────────────────────
 if (!output.name) {
-  output.name = cwd.split('/').pop().toLowerCase().replace(/\s+/g, '-');
+  output.name = basename(cwd).toLowerCase().replace(/\s+/g, '-');
 }
 
 console.log(JSON.stringify(output, null, 2));

skills/ck/commands/resume.mjs

@@ -8,8 +8,8 @@
  * exit 0: success  exit 1: not found
  */
 
+import { existsSync } from 'fs';
 import { resolveContext, renderBriefingBox } from './shared.mjs';
-import { execSync } from 'child_process';
 
 const arg = process.argv[2];
 const cwd = process.env.PWD || process.cwd();
@@ -25,16 +25,11 @@ const { context, projectPath } = resolved;
 
 // Attempt to cd to the project path
 if (projectPath && projectPath !== cwd) {
-  try {
-    const exists = execSync(`test -d "${projectPath}" && echo yes || echo no`, {
-      stdio: 'pipe', encoding: 'utf8', timeout: 2000,
-    }).trim();
-    if (exists === 'yes') {
-      console.log(`→ cd ${projectPath}`);
-    } else {
-      console.log(`⚠  Path not found: ${projectPath}`);
-    }
-  } catch { /* non-fatal */ }
+  if (existsSync(projectPath)) {
+    console.log(`→ cd ${projectPath}`);
+  } else {
+    console.log(`⚠  Path not found: ${projectPath}`);
+  }
 }
 
 console.log('');

skills/ck/commands/save.mjs

@@ -85,7 +85,7 @@ if (isInit) {
   };
   writeProjects(projects);
 
-  console.log(`✓ Project '${contextDir}' registered.`);
+  console.log(`✓ Project '${name}' registered.`);
   console.log(`  Use /ck:save to save session state and /ck:resume to reload it next time.`);
   process.exit(0);
 }

skills/ck/commands/shared.mjs

@@ -165,9 +165,10 @@ export function gitSummary(projectPath, sinceDate) {
   const commits = log.split('\n').filter(Boolean).length;
   if (commits === 0) return null;
 
-  // Count unique files changed across those commits
-  const diff = runGit(`diff --shortstat HEAD@{$(git -C "${projectPath}" rev-list --count HEAD --since="${sinceDate}")}..HEAD 2>/dev/null`, projectPath)
-    || runGit(`diff --shortstat HEAD~${Math.min(commits, 50)}..HEAD`, projectPath);
+  // Count unique files changed: use a separate runGit call to avoid nested shell substitution
+  const countStr = runGit(`rev-list --count HEAD --since="${sinceDate}"`, projectPath);
+  const revCount = countStr ? parseInt(countStr, 10) : commits;
+  const diff = runGit(`diff --shortstat HEAD~${Math.min(revCount, 50)}..HEAD`, projectPath);
 
   if (diff) {
     const filesMatch = diff.match(/(\d+) file/);
@@ -196,7 +197,7 @@ export function renderContextMd(ctx) {
   const latest = ctx.sessions?.[ctx.sessions.length - 1] || null;
   const lines = [
     `<!-- Generated by ck v2 — edit context.json instead -->`,
-    `# Project: ${ctx.name}`,
+    `# Project: ${ctx.displayName ?? ctx.name}`,
     `> Path: ${ctx.path}`,
   ];
   if (ctx.repo) lines.push(`> Repo: ${ctx.repo}`);
@@ -282,7 +283,7 @@ export function renderBriefingBox(ctx, meta = {}) {
 
   const lines = [
     `┌${'─'.repeat(W)}┐`,
-    `│  RESUMING: ${pad(ctx.name, W - 12)}│`,
+    `│  RESUMING: ${pad(ctx.displayName ?? ctx.name, W - 12)}│`,
     `│  Last session: ${pad(`${when}  |  Sessions: ${sessions}`, W - 16)}│`,
   ];
   if (shortSessId) lines.push(`│  Session ID: ${pad(shortSessId, W - 14)}│`);
@@ -318,7 +319,7 @@ export function renderInfoBlock(ctx) {
   const latest = ctx.sessions?.[ctx.sessions.length - 1] || {};
   const sep = '─'.repeat(44);
   const lines = [
-    `ck: ${ctx.name}`,
+    `ck: ${ctx.displayName ?? ctx.name}`,
     sep,
   ];
   lines.push(`PATH     ${ctx.path}`);
@@ -352,7 +353,7 @@ export function renderListTable(entries, cwd, todayStr) {
     const statusLabel = icon === '●' ? '● Active' : icon === '◐' ? '◐ Warm' : '○ Stale';
     const sessId = latest.id ? latest.id.slice(0, 8) : '—';
     const summary = (latest.summary || '—').slice(0, 34);
-    const displayName = (e.name + (isHere ? ' <-' : '')).slice(0, 18);
+    const displayName = ((e.context?.displayName ?? e.name) + (isHere ? ' <-' : '')).slice(0, 18);
     return {
       num: String(i + 1),
       name: displayName,

skills/ck/hooks/session-start.mjs

@@ -86,6 +86,9 @@ function main() {
   const projects = readJson(PROJECTS_FILE) || {};
   const entry = projects[cwd];
 
+  // Read previous session BEFORE overwriting current-session.json
+  const prevSession = readJson(CURRENT_SESSION);
+
   // Write current-session.json
   try {
     writeFileSync(CURRENT_SESSION, JSON.stringify({
@@ -108,17 +111,17 @@ function main() {
       const latest = context.sessions?.[context.sessions.length - 1] || {};
       const sessionDate = latest.date || context.createdAt;
       const sessionCount = context.sessions?.length || 0;
+      const displayName = context.displayName ?? context.name;
 
       // ── Compact summary block (~100 tokens) ──────────────────────────────
       const summaryLines = [
-        `ck: ${context.name} | ${daysAgo(sessionDate)} | ${sessionCount} session${sessionCount !== 1 ? 's' : ''}`,
+        `ck: ${displayName} | ${daysAgo(sessionDate)} | ${sessionCount} session${sessionCount !== 1 ? 's' : ''}`,
         `Goal: ${context.goal || '—'}`,
         latest.leftOff ? `Left off: ${latest.leftOff.split('\n')[0]}` : null,
         latest.nextSteps?.length ? `Next: ${latest.nextSteps.slice(0, 2).join(' · ')}` : null,
       ].filter(Boolean);
 
       // ── Unsaved session detection ─────────────────────────────────────────
-      const prevSession = readJson(CURRENT_SESSION);
       if (prevSession?.sessionId && prevSession.sessionId !== sessionId) {
         // Check if previous session ID exists in sessions array
         const alreadySaved = context.sessions?.some(s => s.id === prevSession.sessionId);
@@ -141,7 +144,7 @@ function main() {
 
       parts.push([
         `---`,
-        `## ck: ${context.name}`,
+        `## ck: ${displayName}`,
         ``,
         summaryLines.join('\n'),
       ].join('\n'));