v2.78.0

Self-hosted ZenNotes server 2.78.0 with the pinned browser artifact web-2.78.0-web.h769e1b278b8e65b3 (built from ZenNotes/zennotes 52ab86fd, the v2.78.0 release commit).

What changed for self-hosters:

• Note covers: a wide banner image across the top of a note, picked from the keyboard (Space l c in Vim mode, Add Cover in the command palette, or :cover): gradients, public-domain photographs, images already in the vault, or an https link. A cover is saved as banner: "![[assets/...]]" frontmatter (the keys Obsidian's banner plugins read), and its image is written through the server's asset endpoints like a pasted image, so it lives in your vault's assets folder. Settings, Typography, Note covers picks Scroll with note, Pinned or Hidden (note_cover_placement under [appearance]).
• Math in Mermaid labels: $$...$$ in a label is typeset with KaTeX, and labels on a fill you chose stay readable in every theme (Pele 1.12.0).
• The Themes picker keeps your theme while you type, and finds a family named with its mode, such as "apple light".
• Ticking tasks in notes saved with Windows line endings acts on the right task and keeps the endings.

The server's Go code is unchanged since 2.77.0, and no Go dependency moved, so vendorHash stays. Its own task-line parser needed no change for Windows line endings: it normalizes \r\n before parsing and has no toggle of its own.

Verification before publication: CI passed on #47 (go on macOS, Ubuntu and Windows, docker and nix). Every released binary matches SHA256SUMS, and the manifest asset is the committed pin byte for byte; with a scratch config and vault, the released darwin-arm64 binary reported v2.78.0, served the app, answered 401 without the token and returned the scratch vault with it, and the embedded bundle carries the cover picker and noteCoverPlacement.

Docker: adibhanna/zennotes:2.78.0, 2.78 and latest are published from this tag by the repository's Docker publisher (linux/amd64 and linux/arm64, one digest).