fix(wallpaper): Revoke blob URL only after new one is set

[prem-k-r]

Fixed wallpaper disappearing on load due to blob URL being revoked too early

Closes #169
Supersedes #206

Overview

This PR fixes a bug where wallpapers could disappear on load because a background blob URL was revoked too early. The change ensures the old object URL is revoked only after a new one has been created and applied, preventing the race condition that made wallpaper images unavailable. This closes issue #169 and supersedes PR #206.

Changes

scripts/wallpaper.js

• Added module-level currentBgUrl to track the active background object URL.
• Introduced setBackground(blob) helper that:
  • Creates a new object URL, applies it to --bg-image and data-bg, then revokes the previous object URL (revocation occurs after the new URL is set).
  • Updates currentBgUrl.
• Refactored all background-setting flows (user uploads, fetched random images, and IndexedDB restoration) to use setBackground() instead of creating ad-hoc URL.createObjectURL and manually revoking URLs.
• Random-image fetch flow now converts responses to blobs, saves them to IndexedDB, and applies them via setBackground() (removed previous delayed-revocation logic).
• On restore from IndexedDB, applies stored blobs via setBackground() and re-fetches daily random images when the stored timestamp is not from the current day.
• Clear-background flow now revokes and nulls currentBgUrl before removing the --bg-image CSS property and switching to color mode.
• Minor reordering of listener wiring and the initial checkAndUpdateImage() call to align with the refactored lifecycle.

CHANGELOG.md

• Added an [Unreleased] → Fixed entry documenting the wallpaper disappearance fix.

manifest.json / manifest(firefox).json

• No version bump in these files in this branch (both remain at 3.3.504 in the repository snapshot).

style.css

• Added placeholder styling rule for inputs in shortcut settings: .shortcutSettingsEntry input::placeholder.
• Adjusted spacing for .shortcutInputRow:last-child.

Problem Solved

Fixes issue #169: prevents automatic removal of user-set wallpapers by ensuring object URLs are revoked only after a new background has been applied. Wallpapers should now persist across browser sessions and days until changed by the user or the extension is reset/uninstalled.

Impact

• No exported/public API changes; changes are internal to the wallpaper lifecycle management.
• Review effort: Medium (behavior-critical fix affecting image lifecycle, persistence, and IndexedDB interactions).

[coderabbitai]

Actionable comments posted: 1

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Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@scripts/wallpaper.js`:
- Around line 19-25: The function setBackground currently revokes currentBgUrl
before creating and applying the new object URL, risking loss of the background
if creation or application fails; change the order in setBackground so you first
call URL.createObjectURL(blob) to get newUrl, apply it via
document.body.style.setProperty("--bg-image", `url(${newUrl})`) and update
currentBgUrl, and only after successful creation/application call
URL.revokeObjectURL on the old currentBgUrl (using the existing currentBgUrl
variable), ensuring you reference the same identifiers (setBackground,
currentBgUrl, URL.createObjectURL, URL.revokeObjectURL,
document.body.style.setProperty).

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Fix all unresolved CodeRabbit comments on this PR:

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📥 Commits

Reviewing files that changed from the base of the PR and between 4bf4e03 and 17dc709.

📒 Files selected for processing (2)

• CHANGELOG.md
• scripts/wallpaper.js