feat(linkedin): progressive onboarding — hide score until 3+ posts, suppress voice guardian noise

- session-start.mjs: count published posts, gate personalization score
  display and reminder behind >= 3 published posts
- voice-guardian.md: suppress LOW CONFIDENCE messages, silently skip
  drift scoring when < 5 samples
- state-file.template.md: add "general" default for expertise_areas
- onboarding.md: show friendly defaults message for new users, move
  score dashboard to returning-user flow

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

plugins/linkedin-thought-leadership/hooks/scripts/session-start.mjs

@@ -162,6 +162,13 @@ if (existsSync(STATE_FILE)) {
     // Non-critical: don't block session start on pruning failure
   }
 
+  // Count published posts for progressive onboarding
+  const recentPostsSection = stateContent.match(/^## Recent Posts\n([\s\S]*?)(?=\n## [^R]|\n## $|$)/m);
+  let publishedPostCount = 0;
+  if (recentPostsSection) {
+    publishedPostCount = (recentPostsSection[1].match(/^\s*[-\[]/gm) || []).length;
+  }
+
   // Build status line
   let statusLine = `LinkedIn: ${postsThisWeek}/${weeklyGoal} posts this week | Streak: ${currentStreak} days`;
   if (lastPostDate && lastPostDate !== 'null') {
@@ -177,12 +184,14 @@ if (existsSync(STATE_FILE)) {
     statusLine += ` | ${followerCount}/${followerTarget} followers (${milestonePhase})`;
   }
 
-  // Personalization score
+  // Personalization score (only show after 3+ published posts — progressive onboarding)
   let pScore = null;
   try {
     const { score } = calculateScore(PLUGIN_ROOT);
     pScore = score;
-    statusLine += ` | Personalization: ${score}%`;
+    if (publishedPostCount >= 3) {
+      statusLine += ` | Personalization: ${score}%`;
+    }
   } catch { /* ignore */ }
 
   // New creator window
@@ -272,8 +281,8 @@ if (existsSync(STATE_FILE)) {
     reminders += `- ${weekRemaining} posts remaining to hit weekly goal of ${weeklyGoal}. It's late in the week.\\n`;
   }
 
-  // Personalization score check
-  if (pScore !== null && pScore < 50) {
+  // Personalization score check (only after 3+ posts — progressive onboarding)
+  if (pScore !== null && pScore < 50 && publishedPostCount >= 3) {
     reminders += `- Personalization score is ${pScore}%. Run /linkedin:setup to improve content quality with your real voice, case studies, and audience data.\\n`;
   }