chore(everything): drop the unused jszip dependency #5471

Found while working the monthly dependency refresh (#5417).

src/everything/package.json declares jszip as a runtime dependency, but nothing in the server imports it:

grep -rn "jszip\|JSZip" src/everything --exclude-dir=node_modules --exclude-dir=dist
# src/everything/package.json:  "jszip": ...

(gzip-file-as-resource compresses with Node's zlib, not jszip.) So every install of @modelcontextprotocol/server-everything pulls in jszip and its transitive tree for no reason, and each dependency sweep reports it.

Expected: remove jszip from src/everything/package.json and the lockfile, with a patch changeset. No behavior change.