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/.claude-plugin/plugin.json

@@ -0,0 +1,11 @@
+{
+  "name": "linkedin-studio",
+  "version": "3.0.0",
+  "description": "LinkedIn Studio — full-spectrum LinkedIn content engine: feed posts, carousels, video scripts, and long-form newsletter editions, with the January 2026 360Brew algorithm baked in. v3.0.0 renames the plugin (was `linkedin-thought-leadership`): the slug, agent namespace, and runtime state-file path are now `linkedin-studio` — the `/linkedin:*` commands are unchanged. Breaking: reinstall required and the state file moves to `~/.claude/linkedin-studio.local.md`.",
+  "author": {
+    "name": "Kjell Tore Guttormsen"
+  },
+  "license": "MIT",
+  "repository": "https://git.fromaitochitta.com/open/ktg-plugin-marketplace",
+  "keywords": ["linkedin", "content-creation", "newsletter", "analytics", "360brew"]
+}