release: bump version to v3.7.2 and update CHANGELOG

Author: ThisIs-Developer

CHANGELOG.md

@@ -3,6 +3,18 @@
 All notable code changes to **Markdown Viewer** are documented here.
 Non-code commits (documentation, planning, README-only updates) are excluded.
 
+## v3.7.2
+
+- **Description:** Implemented custom editor history, a new clear document action, tab layout enhancements, and visual optimizations for theme switching.
+  - **Editor Undo/Redo & Actions:** Implemented custom, robust in-memory document editing history state trackers (Undo/Redo stack) and added a dedicated "Clear Document" toolbar button.
+  - **Tabs Layout & Overflow:** Relocated the "New Tab" button and engineered dynamic container overflow handling to prevent navigation toolbar wrap.
+  - **Mermaid.js Theme Change Synchronization:** Deferred diagram re-rendering and added synchronized fade transitions during theme changes to prevent structural canvas errors, while preserving instant color switches.
+  - **Accessibility & CSS Refactoring:** Removed redundant mobile layout direction buttons; enabled window scroll on mobile viewports for menu access; and cleaned up outer layout scrollbars.
+- **Date:** 2026-06-03
+- **URL:** https://github.com/ThisIs-Developer/Markdown-Viewer/commit/4a9cc6a0b602a377a1e30e64205fff7733472ed8
+
+---
+
 ## v3.7.1
 
 - **Description:** Scoped performance optimizations, accessibility remediation, onboarding template stabilization, and library upgrades.

RELEASE_NOTES_v3.7.2.md

@@ -0,0 +1,58 @@
+# Markdown Viewer - Release Notes v3.7.2
+**Date:** June 3, 2026  
+**Commit Range:** `fe19aa47e5710e4ede39afde89b1591b6777fab1` to `4a9cc6a0b602a377a1e30e64205fff7733472ed8`
+
+We are excited to announce the release of **v3.7.2** of Markdown Viewer! This version introduces substantial quality-of-life enhancements, layout adjustments to prevent broken UI behaviors on heavy tabs, and visual transitions that optimize the experience during dark/light mode swaps.
+
+---
+
+## Key Highlights
+
+### 1. Robust Custom Editor History (Undo & Redo) & Document Clearing
+Previously, relying on simple input updates caused loss of edit state tracking. In this release, we have built a custom, tab-aware edit history state manager:
+- **Undo / Redo Stack:** Users can seamlessly revert or redo edits with high granularity.
+- **Clear Document Action:** Added a dedicated "Clear Document" button in the editor toolbar, which wipes the editor pane instantly with a clean history state transition.
+
+### 2. Tab Navigation & Dynamic Overflow Handling
+Managing multiple open tabs on small viewports could previously wrap or push the layout off-screen.
+- **Relocated "New Tab" Button:** Positioned strategically for better accessibility.
+- **Dynamic Overflow Handling:** The tab list now dynamically detects space constraints and groups overflowing tabs into a clean UI structure, protecting the header layout from wrapping.
+
+### 3. Mermaid.js Theme Change Transitions & Stabilization
+Swapping themes (Light $\leftrightarrow$ Dark) previously caused Mermaid.js canvases to break or reload abruptly.
+- **Deferred Re-rendering:** Mermaid diagram rendering is now debounced and deferred to prioritize the immediate repaint of CSS color schemas.
+- **Synchronized Transitions:** A smooth fade-in/fade-out transition occurs when diagrams redraw under the new theme.
+- **Original Instant Color Switching:** Reverted full-page body transitions to ensure the color switches remain fast, lightweight, and responsive.
+
+### 4. Layout Cleanups & Mobile Accessibility
+- **Mobile Direction Toggle:** Removed the redundant LTR/RTL button from the mobile header, as it is already present in the formatting toolbar.
+- **Viewport Scroll Accessibility:** Enabled window scroll on mobile viewports to allow full access to sidebar menu controls on small screens.
+- **Outer Scrollbar Cleanup:** Fixed styling variables to remove redundant outer window scrollbars on desktop builds.
+
+---
+
+## Detailed Commit Log
+
+The following commits are packaged into this release:
+
+* **`4a9cc6a`** — Merge pull request #153 from ThisIs-Developer/feature/global-new-tab-and-overflow
+* **`e379725`** — chore(desktop): sync desktop resources with latest tab enhancements
+* **`e205b67`** — feat(tabs): relocate new tab button and implement overflow handling
+* **`542472b`** — fix(layout): allow window scroll on mobile viewports for menu accessibility
+* **`071cc30`** — chore(desktop): sync desktop-app resources with web-app fixes
+* **`f4d31db`** — Merge branch 'fix/mermaid-theme-change'
+* **`076620e`** — fix(layout): remove outer window scrollbar
+* **`a611966`** — Merge pull request #151 from ThisIs-Developer/fix/mermaid-theme-change
+* **`533e03b`** — perf(theme): restore original main branch instant theme changing code with raw source preservation
+* **`2257f22`** — perf(theme): revert full-page transitions to restore fast, lightweight color switches
+* **`79c17b8`** — style(theme): implement unified 300ms full-page theme switch transition
+* **`6763234`** — style(mermaid): implement smooth synchronized fade transitions on theme switch
+* **`47dab15`** — perf(mermaid): defer diagram re-rendering to keep theme transition smooth
+* **`83dcff5`** — chore(desktop): sync desktop-app resources with web-app fixes
+* **`b8eb522`** — fix(mermaid): prevent diagrams from breaking on theme change
+* **`b5fa206`** — Merge pull request #150 from ThisIs-Developer/fix/undo-redo-clear-document
+* **`e5034fb`** — fix: implement custom editor history (undo/redo) and clear document action
+* **`fe19aa4`** — Remove mobile direction toggle button as it is already in the toolbar
+
+---
+*For issues, feedback, or contribution, please open a ticket on GitHub.*

desktop-app/resources/js/script.js

@@ -48,7 +48,7 @@ document.addEventListener("DOMContentLoaded", function () {
 
   // View Mode State - Story 1.1
   let currentViewMode = 'split'; // 'editor', 'split', or 'preview'
-  const APP_VERSION = '3.7.1';
+  const APP_VERSION = '3.7.2';
   let activeModal = null;
   let lastFocusedElement = null;
   let isFindModalOpen = false;

script.js

@@ -48,7 +48,7 @@ document.addEventListener("DOMContentLoaded", function () {
 
   // View Mode State - Story 1.1
   let currentViewMode = 'split'; // 'editor', 'split', or 'preview'
-  const APP_VERSION = '3.7.1';
+  const APP_VERSION = '3.7.2';
   let activeModal = null;
   let lastFocusedElement = null;
   let isFindModalOpen = false;

sw.js

@@ -1,4 +1,4 @@
-const CACHE_NAME = 'markdown-viewer-cache-v3.7.1';
+const CACHE_NAME = 'markdown-viewer-cache-v3.7.2';
 
 // PERF-011: Split precache into critical (local files) and lazy (CDN libraries)
 // Critical assets are precached during SW install for instant offline startup