fix: support Zotero 8 and stabilize citationKey handling

[Ascarshen]

Summary

This PR restores compatibility with Zotero 8 and fixes several related regressions in both the Zotero and Obsidian sides of obsidian-zotlit.

It focuses on three areas:

• Zotero 8 menu and reader API compatibility
• native citationKey / Better BibTeX fallback handling
• Obsidian-side citation insertion and runtime/build fixes

Changes

• added Zotero 8-compatible bootstrap fallback via Services.sys.mjs

• updated item menu registration for Zotero 8

• added MenuManager-based menu support and virtual menu adapters

• updated reader menu/event hooks to support newer reader internals

• hardened annotation update logic for changed reader iframe/window fields

• fixed citekey backend selection in the db worker

• fixed legacy BBT v0 search DB attachment alias

• added fallback to Zotero native citationKey when BBT DBs are unavailable

• fixed load status reporting for native citationKey fallback

• updated Zotero addon compatibility metadata to strict_max_version: 8.*

• fixed Obsidian-side async effect() callback issues

• removed the broken direct dependency on @preact/signals-core

• fixed plugin context typing around use.plugin(this)

• improved template preview and citekey-click behavior for deferred markdown leaves

• fixed JSON request parsing in the local Obsidian server

• fixed citation insertion so stale results no longer render [@undefined]

• updated default citation templates to skip missing citekeys instead of rendering undefined

Validation

• app/zotero typecheck passed
• app/obsidian typecheck passed
• app/obsidian production build passed
• verified literature note creation in a live Zotero + Obsidian setup
• verified citation insertion no longer produces [@undefined]

Notes

This PR contains source-level compatibility fixes only.

I intentionally left local environment-only changes, temporary test fixtures, and unrelated workspace noise out of this branch.

[aidenlx]

Thank you! I'll test this locally and get this merged with some feat port back

[aidenlx]

i would suggest separate Zotero plugin changes from this PR so I can get obsidian plugin PR merged sooner and have an working obsidian plugin first. I haven't develop for Zotero plugins for quite some time so i'll need some time to catch up with the Zotero updates from 6 to 8.

[aidenlx]

btw, i've include an update that remove the custom build for better-sqlite3 from zotlit, you should rebase your branch first in case of conflicts.

[Ascarshen]

Rebased onto latest master and split as requested. ：）

This PR now only keeps the Obsidian-side changes plus the shared citekey/backend pieces needed by the Obsidian plugin:

The Zotero plugin changes have been moved to a separate branch/PR:

• branch: fix/zotero8-plugin
• compare: https://github.com/PKM-er/obsidian-zotlit/compare/master...Ascarshen:fix/zotero8-plugin?expand=1