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/prompts/state-update-reminder.md

@@ -0,0 +1,85 @@
+Before ending this LinkedIn content session, do two things:
+
+**1. Update State File**
+If a post was created or finalized in this session, use the state-updater script:
+```bash
+node --input-type=module -e "
+import { writeState, updatePostTracking } from '${CLAUDE_PLUGIN_ROOT}/hooks/scripts/state-updater.mjs';
+writeState(content => updatePostTracking(content, {
+  postDate: 'YYYY-MM-DD',
+  postTopic: 'topic_area',
+  hookText: 'First 60 chars of hook...',
+  charCount: NNNN,
+  format: 'post'
+}));
+"
+```
+Replace the placeholder values with actual post data from this session.
+
+If the user mentioned or updated their follower count during this session:
+```bash
+node --input-type=module -e "
+import { writeState, updateFollowerCount } from '${CLAUDE_PLUGIN_ROOT}/hooks/scripts/state-updater.mjs';
+writeState(content => updateFollowerCount(content, {
+  count: NNNN,
+  month: 'YYYY-MM'
+}));
+"
+```
+
+- Clear `next_planned_topic` if it was used, or set it to the next suggested topic
+- If analytics data was imported in this session, set `last_import_date` to today (YYYY-MM-DD) and `last_import_week` to current ISO week (YYYY-WXX)
+
+**2. Pre-Publish Reminders** (only if a post was created)
+
+- **Quality Check**: Has content been reviewed against quality scorecard? Hook 110-140 chars, 1,200-1,800 chars total, authentic tone, no external links.
+- **5x5x5 Engagement**: Before posting, complete 15-20 min pre-posting engagement — 5 people with overlapping audiences, find their recent posts, write 5 thoughtful comments (15+ words each).
+- **First-Hour Plan**: Respond within 5 minutes to first comments. Add value in responses. Target 15+ engagements in first hour.
+- **Posting Time**: Post when target audience is most active.
+
+**3. Queue Status Check**
+
+If posts were added to the queue during this session (`assets/drafts/queue.json` was modified):
+- Confirm how many posts were queued and their scheduled dates
+- Remind: "View your full schedule with /linkedin:calendar"
+
+If a scheduled post was published during this session:
+- Verify it was marked as published in queue.json (status = "published")
+- If not, remind: "Run /linkedin:calendar to mark the post as published and update queue status"
+
+Provide reminders naturally based on what was done in the session. If no LinkedIn content was created, skip the reminders and just ensure state is consistent.
+
+**4. Voice Sample Collection** (if a post was created)
+
+If a LinkedIn post was created or finalized in this session, save the full post text as a voice sample:
+
+- Read the full post text from the draft that was just created
+- Check if `assets/voice-samples/authentic-voice-samples.md` exists
+- Append the full post to the `## Collected Post Samples` section:
+  ```
+  ### [YYYY-MM-DD] — [post type] ([char count] chars)
+  [Full post text exactly as written]
+  ```
+- **Ask the user for confirmation** before writing: "I'll save this post as a voice sample for drift detection. OK?"
+- This builds the voice sample library that enables automatic drift scoring (needs 5+ samples for reliable scoring)
+- The more samples collected, the more accurate the voice-trainer's drift detection becomes
+
+**5. Content History Log** (if a post was created)
+
+If a LinkedIn post was created or finalized, append an entry to the content history log:
+
+- If `assets/analytics/content-history.md` does not exist, initialize it from `config/content-history.template.md`
+- Append a new row to the "## Content Log" table:
+  ```
+  | YYYY-MM-DD | "Hook text..." | topic_area | format | word_count | char_count | source |
+  ```
+  Where:
+  - `date`: Today's date
+  - `hook`: First 60 characters of the hook line
+  - `topic`: Matching expertise_area value (for pillar tracking)
+  - `format`: post/quick/react/video/pipeline
+  - `word_count`: Word count of the full post
+  - `char_count`: Character count of the full post
+  - `source`: original/url/curated (where the idea came from)
+- This is append-only — never edit or delete existing entries
+- This log enables `/linkedin:report` and `analytics-interpreter` to track content production over time without requiring LinkedIn CSV imports