feat: fold activity decorator into part grouping (#5608)

* Fold Activity Decorator into Part Grouping Decorator

* Refactor Part Grouping Decorator

* Extract shared styles to variables 1/x

* More variables 2/x

* Cleanup 3/3

* Final touches

* Changelog

* Fix tests

* Achievements

Author: OEvgeny

ACHIEVEMENTS.md

@@ -17,6 +17,25 @@ A curated list of major achievements by the Web Chat team. This document celebra
 
 ## 🧱 Architecture & Core Systems
 
+### 🌐 ES Modules Browser Build
+
+**Goal:** Ship first-class `<script type="module">` bundles for modern browsers.  
+**By:** [@compulim](https://github.com/compulim) in [PR #5592](https://github.com/microsoft/BotFramework-WebChat/pull/5592), [#5593](https://github.com/microsoft/BotFramework-WebChat/pull/5593), [#5595](https://github.com/microsoft/BotFramework-WebChat/pull/5595), [#5600](https://github.com/microsoft/BotFramework-WebChat/pull/5600), [#5602](https://github.com/microsoft/BotFramework-WebChat/pull/5602)
+
+- Delivered browser-ready ES module builds with vendor chunking for optimal caching.
+- Introduced new export entries and reworked external API.
+- Added documentation for all available Web Chat inclusion options.
+
+### 🧠 Part Grouping for Chain-of-Thought
+
+**Goal:** Organize multi-part reasoning flows into collapsible groups within the transcript.  
+**By:** [@OEvgeny](https://github.com/OEvgeny) in [PR #5553](https://github.com/microsoft/BotFramework-WebChat/pull/5553), [#5585](https://github.com/microsoft/BotFramework-WebChat/pull/5585), [#5590](https://github.com/microsoft/BotFramework-WebChat/pull/5590), [#5608](https://github.com/microsoft/BotFramework-WebChat/pull/5608)
+
+- Added logical grouping and context so activities can self-organize via `Message` entity metadata.
+- Introduced a way to render grouped activities and group-aware focus management to keep grouped conversations accessible.
+- Reworked fluent-theme approach to decorating activities.
+- Extended activity ordering to honor entity `position` fields when rendering grouped messages.
+
 ### 🛠️ Migration to `micromark`
 
 **Goal:** Replace `markdown-it` with a modern and extensible markdown parser.  
@@ -139,15 +158,14 @@ A curated list of major achievements by the Web Chat team. This document celebra
 
 ## 🚀 Performance & Developer Experience
 
-
 ### 🧩 Introduction of PolyMiddleware
 
 **Goal:** Enable composable, reusable, and unified way for managing middleware.  
 **By:** [@compulim](https://github.com/compulim) in [PR #5515](https://github.com/microsoft/BotFramework-WebChat/pull/5515), [#5566](https://github.com/microsoft/BotFramework-WebChat/pull/5566)
 
 - Allows multiple middleware to be composed and applied from a single place.
 - Simplifies extension, testing, and maintenance of middleware logic.
-- Lays groundwork for Web Chat becomoming an UI orchestration.
+- Lays groundwork for Web Chat becoming a UI orchestration layer.
 
 ### 🧠 Memoization & Hook Optimizations
 

CHANGELOG.md

@@ -121,7 +121,7 @@ Notes: web developers are advised to use [`~` (tilde range)](https://github.com/
    - `@msinternal/botframework-webchat-react-hooks` for helpers for React hooks
 - Added link sanitization and ESLint rules, in PR [#5564](https://github.com/microsoft/BotFramework-WebChat/pull/5564), by [@compulim](https://github.com/compulim)
 - Added blob URL sanitization and ESLint rules, in PR [#5568](https://github.com/microsoft/BotFramework-WebChat/pull/5568), by [@compulim](https://github.com/compulim)
-- Added visual message grouping following the `isPartOf` property of the `Message` entity, in PR [#5553](https://github.com/microsoft/BotFramework-WebChat/pull/5553), in PR [#5585](https://github.com/microsoft/BotFramework-WebChat/pull/5585), in PR [#5590](https://github.com/microsoft/BotFramework-WebChat/pull/5590), by [@OEvgeny](https://github.com/OEvgeny)
+- Added visual message grouping following the `isPartOf` property of the `Message` entity, in PR [#5553](https://github.com/microsoft/BotFramework-WebChat/pull/5553), in PR [#5585](https://github.com/microsoft/BotFramework-WebChat/pull/5585), in PR [#5590](https://github.com/microsoft/BotFramework-WebChat/pull/5590), in PR [#5608](https://github.com/microsoft/BotFramework-WebChat/pull/5608), by [@OEvgeny](https://github.com/OEvgeny)
    - The mode is suitable for providing chain-of-thought reasoning
    - Added visual indication of `creativeWorkStatus` property in `Message` entity:
       - `undefined` - no indicator is shown