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>

.claude-plugin/marketplace.json

@@ -26,9 +26,9 @@
       "description": "Voyage — brief, research, plan, execute, review, continue. Contract-driven Claude Code pipeline with specialized agent swarms, external research triangulation, adversarial review, post-hoc independent review with Handover 6 feedback loop, multi-session resumption, session decomposition, and headless execution. /trekbrief, /trekplan, and /trekreview each end by building a self-contained operator-annotation HTML (scripts/annotate.mjs, modelled on claude-code-100x): pencil-toggle annotation mode, select text or click any element, pick intent (Fiks/Endre/Spørsmål), comment, Copy Prompt, paste back, Claude revises the .md."
     },
     {
-      "name": "linkedin-thought-leadership",
-      "source": "./plugins/linkedin-thought-leadership",
-      "description": "Build LinkedIn thought leadership with algorithmic understanding, strategic consistency, and authentic engagement. Updated for the January 2026 360Brew algorithm change."
+      "name": "linkedin-studio",
+      "source": "./plugins/linkedin-studio",
+      "description": "LinkedIn Studio — a full-spectrum LinkedIn content engine: feed posts, carousels, video scripts, and long-form newsletter editions, built on algorithmic understanding, strategic consistency, and authentic engagement. Updated for the January 2026 360Brew algorithm change."
     },
     {
       "name": "graceful-handoff",