Markdown editor: Plain-clicking rendered links in Editing mode prevents caret placement

## Description

In the experimental hybrid Markdown editor, rendered links behave like preview links even while the editor is in **Editing** mode. A normal click on a rendered link immediately opens its target (typically in a browser or new tab). This makes it awkward to place the caret in the link text or reveal and edit the Markdown source.

Editing mode should prioritize editing interactions. Opening a link can remain available through Cmd/Ctrl-click or another explicit action; ordinary click-to-open is reasonable in Locked mode.

## Reproduction Steps

1. Open a Markdown document in the experimental Markdown editor and switch to **Editing** mode.
2. Add or locate `[link](https://example.com)`.
3. Ensure the link is rendered (its block is not already active).
4. Ordinary-click the rendered `link` text, intending to place the caret or edit the link text.

## Expected

In Editing mode, an ordinary click places the caret/selects text and reveals the editable Markdown as appropriate. Opening the target requires Cmd/Ctrl-click or an explicit open action. In Locked mode, an ordinary click may open the target.

## Actual

The ordinary click immediately opens `https://example.com`, so the first interaction navigates away instead of placing the caret. Editing the link requires an indirect click elsewhere in the block before returning to the link.

## Root Cause

The current `LinkViewNode` interaction explicitly opens a primary click whenever the link block is inactive (`!blockActive`), regardless of the editor-wide Editing/Locked mode. Only after the block is active does it require Ctrl/Cmd. As a result, the rendered state of the individual block takes precedence over Editing mode.

## Additional Context

This is related to, but distinct from, #323280, which fixed links not opening at all, and #326663, which concerns when link source expands during click-drag selection. The requested behavior is mode-sensitive: ordinary clicks should edit in Editing mode and may open in Locked mode.