Added Support of Markdown Format

[KommunicateDeveloper]

Summary

• Add Markdown detection, parsing, and rendering utilities, and integrate them into message cells

• Introduce KMMarkdownDetector, KMMarkdownParser, and KMMarkdownRenderer leveraging iOS 15 AttributedString Markdown parsing with fallbacks for older OS versions

• Update KMChatMessageBaseCell to:

  • Detect Markdown in incoming (non-self) messages
  • Parse and render Markdown into attributed strings
  • Merge mention styling with the rendered Markdown output
  • Use the combined attributed text for both sizing and display

• Update KMChatFriendMessageCell to:

  • Render reply text using the Markdown parser
  • Apply minor formatting cleanups for constraints and image resource construction

Image

[sentry]

Bug: Height calculation in messageHeight() assumes markdown for all messages, but setMessageText() only renders it for received messages, causing layout bugs for self-sent markdown messages.
_{Severity: MEDIUM}

Suggested Fix

The height calculation logic in messageHeight() should be aligned with the display logic in setMessageText(). It should check if the message is self-sent (viewModel.isMyMessage) and only apply markdown sizing for received messages, matching the rendering behavior.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent.
Verify if this is a real issue. If it is, propose a fix; if not, explain why it's not
valid.

Location: Sources/Views/KMChatMessageBaseCell.swift#L327-L332

Potential issue: There is an inconsistency between message height calculation and
rendering for self-sent messages. The `messageHeight()` method calculates the cell
height assuming markdown is applied to all messages, including those sent by the user.
However, the `setMessageText()` method only renders markdown for received messages. This
causes a mismatch for self-sent messages containing markdown syntax, leading to
incorrect UI rendering, such as text clipping or improper bubble sizing.

_{Did we get this right? 👍 / 👎 to inform future reviews.}