feat(linkedin): integrate state-updater.mjs across all commands and hooks

Replace manual YAML editing instructions with deterministic
state-updater.mjs calls in 8 content commands (post, quick, react,
pipeline, first-post, video, publish, carousel) and 2 hook prompts
(state-update-reminder, post-creation-automation). Batch.md gets note
that state updates happen at publish time.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

plugins/linkedin-thought-leadership/commands/post.md

@@ -173,14 +173,20 @@ Before they post, remind them:
 - Target: 15+ engagements in first hour
 
 **State Update:**
-After the post is finalized, update `~/.claude/linkedin-thought-leadership.local.md`:
-- Set `last_post_date` to today's date (YYYY-MM-DD)
-- Set `last_post_topic` to the main topic
-- Check if ISO week changed — if so, reset `posts_this_week` to 0, update `current_week`
-- Increment `posts_this_week`
-- Update streak: increment if consecutive day, reset to 1 if gap > 2 days
-- Update `longest_streak` if current exceeds it
-- Add entry to "## Recent Posts": [YYYY-MM-DD] "Hook text..." (char count) - topic
+After the post is finalized, update state deterministically:
+```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: 'Hook text here...',
+  charCount: NNNN,
+  format: 'post'
+}));
+"
+```
+Replace placeholders with actual post data. This replaces manual YAML editing.
 
 ## Reference Files