refactor(linkedin)!: rename plugin linkedin-thought-leadership → linkedin-studio (v3.0.0)

BREAKING CHANGE: the marketplace slug, the agent namespace
(linkedin-studio:<agent>), and the runtime state-file path
(~/.claude/linkedin-studio.local.md) all change. Reinstall required;
existing state migrated in place (post metrics, streak, history preserved).
The /linkedin:* commands are unchanged — the command namespace is set
per-command in frontmatter and was always independent of the plugin slug.
Functionality is byte-identical to v2.4.0; this release is pure identity.

- dir + manifests: plugins/linkedin-studio + plugin.json + root marketplace.json
- agent namespace updated in commands/newsletter.md (only functional invoker)
- state path updated in 4 hook scripts + topic-rotation prompt + state template
- catch-all skill dir renamed skills/linkedin-studio (5 functional skills unchanged)
- docs + version bump to 3.0.0 across README badge, CHANGELOG, root README/CLAUDE.md
- historical records (CHANGELOG past entries, docs/ build artifacts,
  config-audit v5.0.0 snapshots) intentionally retain the old slug

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

plugins/linkedin-studio/hooks/scripts/clipboard-helper.mjs

@@ -0,0 +1,102 @@
+#!/usr/bin/env node
+// Cross-platform clipboard helper for linkedin-studio plugin
+// Copies text to system clipboard using platform-native commands.
+// Standalone: reads stdin and copies it. Import: export { copyToClipboard, clipboardAvailable }
+
+import { execSync } from 'node:child_process';
+import { dirname } from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const PLATFORM_COMMANDS = {
+  darwin: { copy: 'pbcopy', check: 'which pbcopy' },
+  win32: { copy: 'clip', check: 'where clip' },
+  linux: { copy: 'xclip -selection clipboard', check: 'which xclip' },
+};
+
+const LINUX_FALLBACK = { copy: 'xsel --clipboard --input', check: 'which xsel' };
+
+/**
+ * Check if clipboard is available on this platform.
+ * @returns {{ available: boolean, platform: string }}
+ */
+export function clipboardAvailable() {
+  const platform = process.platform;
+  const commands = PLATFORM_COMMANDS[platform];
+
+  if (!commands) {
+    return { available: false, platform };
+  }
+
+  try {
+    execSync(commands.check, { stdio: 'ignore' });
+    return { available: true, platform };
+  } catch {
+    // Linux fallback: try xsel if xclip not found
+    if (platform === 'linux') {
+      try {
+        execSync(LINUX_FALLBACK.check, { stdio: 'ignore' });
+        return { available: true, platform };
+      } catch {
+        return { available: false, platform };
+      }
+    }
+    return { available: false, platform };
+  }
+}
+
+/**
+ * Copy text to the system clipboard.
+ * Never throws — always returns a result object.
+ * @param {string} text - The text to copy
+ * @returns {{ success: boolean, platform: string }}
+ */
+export function copyToClipboard(text) {
+  const platform = process.platform;
+
+  if (typeof text !== 'string') {
+    return { success: false, platform };
+  }
+
+  const commands = PLATFORM_COMMANDS[platform];
+  if (!commands) {
+    return { success: false, platform };
+  }
+
+  // Determine which copy command to use
+  let copyCmd = commands.copy;
+  if (platform === 'linux') {
+    try {
+      execSync(commands.check, { stdio: 'ignore' });
+    } catch {
+      try {
+        execSync(LINUX_FALLBACK.check, { stdio: 'ignore' });
+        copyCmd = LINUX_FALLBACK.copy;
+      } catch {
+        return { success: false, platform };
+      }
+    }
+  }
+
+  try {
+    execSync(copyCmd, { input: text, stdio: ['pipe', 'ignore', 'ignore'] });
+    return { success: true, platform };
+  } catch {
+    return { success: false, platform };
+  }
+}
+
+// Standalone execution: read stdin and copy
+if (process.argv[1] === fileURLToPath(import.meta.url)) {
+  let input = '';
+  process.stdin.setEncoding('utf-8');
+  process.stdin.on('data', (chunk) => { input += chunk; });
+  process.stdin.on('end', () => {
+    const result = copyToClipboard(input);
+    if (result.success) {
+      process.stdout.write('COPIED\n');
+    } else {
+      process.stdout.write(`FAILED:${result.platform}\n`);
+      process.exitCode = 1;
+    }
+  });
+}