#161 - Fix expand in edit mode with Readable line length

[aioue]

Summary

This continues the work from #161.

You already added expand for reading mode and shared a test build. This PR fixes the remaining live-preview / edit-mode case when Readable line length is turned on.

This took a while 😪

What users should see

With Readable line length on, in live preview:

• A normal code block stays in the usual narrow centered column.
• An expand block that is wrapped lines up with that same column (same left edge and width) and soft-wraps long lines.
• An expand block that is unwrapped stays left-aligned with the column, but grows as wide as the longest line. If it is wider than the pane, you scroll the editor horizontally.
• The Plain text label and wrap button stay on screen even when the window is narrow or the block is wider than the pane.
• Code blocks inside callouts are left alone (same as reading mode).

What changed (high level)

• New edit-mode layout helper (Expand.ts) that cooperates with Obsidian’s readable-line CSS variables instead of fighting them.
• Unwrapped width comes from the existing wrap/unwrap decorations (per block), and updates when you type.
• Horizontal scroll uses the editor scroller for expand blocks (no extra per-block scrollbar).
• Button position is adjusted with right only, so the language label does not get crushed into a vertical stack.

How to test

1. Turn Readable line length on.
2. Open a note in live preview with a normal fence and a ```lang expand ` fence that has a long line.
3. Confirm the expand block matches the normal column when wrapped, and grows when unwrapped.
4. Narrow the window while unwrapped - the text can scroll, but Plain text / wrap should stay visible.
5. Optional: try a titled expand block (title:...), and a note with a callout code block above an expand block.

Built styles.css is included. main.js is left unchanged in git (same as the repo’s usual release flow) - please rebuild for a release artifact.

Thanks again for implementing the first pass on #161 - happy to adjust based on review.

[mugiwara85]

@aioue Wasn't this working correctly? If I remember correctly (I might be wrong) it worked for me also when "readable line length" was enabled/disabled. Anyway, thanks for PR. I will look at it, but unfortunately it could take some time. I am currently under a "little" more workload than usually 😄

[aioue]

Unfortunately not, it didn't change the codeblock size or extend the text. Of course, happy to wait. If you think it's too much change to merge, that's ok too.

[mugiwara85]

Ah ok. I will definitely check out, what you did :)