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-thought-leadership/agents/fixtures/fact-checker-cases.md

@@ -1,52 +0,0 @@
-# Fact-Checker Fasit Fixture
-
-Three reference claims with known ground truth, used to sanity-check the
-`fact-checker` agent. Each case states the claim, the **fasit** (the correct
-answer + why), and the expected risk verdict.
-
-- 🟢 = verified true against a primary/credible source
-- 🔴 = contradicted by evidence (false), or a high-risk claim asserted without support
-- 🟡 = unverifiable from available sources — flagged, never guessed
-
-This file is a *fasit*, not a test harness. The structural lint lives in
-`agents/__tests__/fact-checker-fixture.test.mjs`. Whether the agent's live
-output actually reproduces these verdicts is `[GATE]`/`[OPERATØR]` — it is
-not self-certified.
-
-Each case block below carries exactly one verdict emoji (in its **Verdict**
-field); the prose deliberately avoids emoji so the structural lint can read a
-single, unambiguous verdict per case.
-
----
-
-## Case 1 — verifiable true
-
-- **Claim:** The EU AI Act entered into force on 1 August 2024.
-- **Verdict:** 🟢
-- **Fasit:** True. Regulation (EU) 2024/1689 was published in the Official
-  Journal on 12 July 2024 and entered into force 20 days later, on
-  1 August 2024. This is confirmable against the primary source (EUR-Lex)
-  and the European Commission's own communications. A correct agent run
-  returns the verified verdict with a primary-source citation.
-
-## Case 2 — verifiable false
-
-- **Claim:** GPT-4 was developed and released by Anthropic.
-- **Verdict:** 🔴
-- **Fasit:** False. GPT-4 was released by OpenAI (March 2023). Anthropic
-  develops the Claude model family. The claim is contradicted by both
-  vendors' primary documentation. A correct agent run returns the high-risk
-  verdict and names the contradicting source — it must not soften a
-  contradicted claim to the unverified tier.
-
-## Case 3 — unverifiable
-
-- **Claim:** A Norwegian public-sector agency cut its case-handling time by
-  exactly 37% in Q3 2025 after deploying an internal AI assistant.
-- **Verdict:** 🟡
-- **Fasit:** Unverifiable. No named agency, no published report, and no
-  primary source exists for this precise figure; an internal operational
-  metric of this kind is not independently confirmable from open sources.
-  A correct agent run returns the unverified verdict and states explicitly
-  that the claim cannot be verified — it must not fill the gap by inventing
-  a plausible source or promoting the claim to the verified tier.