[Bug / Feature] No "Collapse All" button after collection import — all folders expand by default (v13.1.0)

[manikandan-findmyhub]

Summary

When importing a large collection (YAML v5.1 format), all folders
expand by default. There is no native "Collapse All" button or
working keyboard shortcut to collapse all folders at once in
Insomnia 13.1.0.

Environment

• Insomnia version: 13.1.0
• OS: Windows 11
• Collection size: 485 endpoints across 92 folders (3 levels deep)
• Import format: YAML v5.1 (collection.insomnia.rest/5.0)

Steps to Reproduce

1. Export a collection as YAML v5.1
2. Import the YAML via File → Import
3. Open the collection in the Debug workspace
4. Observe: all 92 folders are fully expanded

Expected Behavior

• Folders should default to collapsed state after import
• OR a Collapse All button/shortcut should be available to
  collapse all folders instantly

Actual Behavior

• All folders are expanded after every import
• No "Collapse All" button is visible in the sidebar
• Alt + Left Arrow collapses only one folder at a time —
  requires 100+ manual clicks for large collections
• Ctrl + \ does not reset sidebar state

Context

• PR chore(Minor UI improvements): Expand/Collapse all and file card titles #7528 (Jun 2024) added an "Expand/Collapse all button for
  sidebar" — but this button is not present in v13.1.0
• Discussion Expand/Collapse All for tree view #3589 was marked as "answered" by a maintainer in
  Sep 2024 with a screenshot, but the feature appears missing in
  the current release
• The v5.1 YAML schema (MetaGroupSchema) has no collapsed
  field, so import always resets folder state regardless of
  previous UI state

Proposed Solutions (either would fix this)

Option A — Restore the Collapse All button (was in PR #7528):
Add the collapse/expand all toggle button back to the sidebar
toolbar above the folder tree.

Option B — Persist collapsed state in YAML schema:
Add collapsed: boolean to MetaGroupSchema in
import-v5-parser.ts, so exported YAML preserves the user's
folder state and restores it on import.

Option C — Default to collapsed on import:
When importing a collection for the first time, default all
folders to collapsed: true instead of expanded.

Impact

With 485 endpoints across 92 folders, every import requires
manually collapsing 92 folders one by one. This makes
re-importing updated collections very painful for teams that
regularly sync collections via Git or CI.