docs(linkedin): update documentation for v1.2.0 friction reduction release

Version bump v1.1.0 → v1.2.0 across all docs (CLAUDE.md, README.md,
root README.md, plugin.json, CHANGELOG.md). Documents new scripts
(state-updater, clipboard-helper, ical-generator), reduced interactive
steps, auto-clipboard, progressive onboarding, and MCP carousel pipeline.

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

plugins/linkedin-thought-leadership/CHANGELOG.md

@@ -5,6 +5,25 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.2.0] - 2026-04-11
+
+### Summary
+Friction reduction release. Fewer interactive steps, auto-clipboard, deterministic state management, and progressive onboarding.
+
+### Added
+- **`clipboard-helper.mjs`** — cross-platform clipboard utility (macOS `pbcopy`, Linux `xclip`/`xsel`, WSL `clip.exe`). All 8 content commands auto-copy output to clipboard
+- **`state-updater.mjs`** — deterministic state mutations: `updatePostTracking`, `pruneContentHistory`, `updateFollowerCount`. Pure functions with 19 tests. No AI involvement in state updates
+- **`ical-generator.mjs`** — RFC 5545 calendar file generation for batch scheduling. VALARM reminders, VTIMEZONE support, line folding, special character escaping. 16 tests
+- **MCP image carousel pipeline** — `/linkedin:carousel` generates professional slide images via mcp-image (1080x1350, 3:4 ratio) with text overlays. Mermaid Chart and text-based fallbacks
+- **Progressive onboarding** — personalization score hidden until 3+ posts; voice guardian suppressed until 5+ voice samples; reasonable defaults in state template
+- **iCal integration in batch** — `/linkedin:batch` generates `.ics` file importable into macOS Calendar, Google Calendar, and Outlook
+- **Auto-prune content history** — session-start dynamically imports `pruneContentHistory` to remove entries older than 90 days
+
+### Changed
+- **Reduced interactive steps** — angle, format, and post type inferred from context. Max 2 questions per post (down from 4-6) in `post`, `quick`, `react`, `pipeline`
+- **State management** — Stop hook and 8 commands now reference `state-updater.mjs` for deterministic writes instead of AI-driven YAML editing
+- **State file template** — default expertise area changed from domain-specific to `"general"` for better new-user experience
+
 ## [1.1.0] - 2026-04-08
 
 ### Summary