Upgrade Node.js dependencies across workspaces (targeting next)

[data-douser]

Upgrade Node.js dependencies across server and extensions/vscode workspaces, and bump the minimum required Node.js version to >=25.6.0.

Supersedes #237 (rebased onto next to avoid merging to main before the pending v2.25.2 release).

Dependency upgrades

Tooling & formatting (all workspaces)

Package	From	To
eslint	^10.1.0	^10.2.0
prettier	^3.8.1	^3.8.2
typescript-eslint	^8.57.2 / ^8.58.0	^8.58.1

Type definitions & testing (server + extensions/vscode)

Package	From	To
@types/node	^25.5.0	^25.6.0
@types/vscode	^1.110.0	^1.115.0
@vitest/coverage-v8	^4.1.2	^4.1.4
vitest	^4.1.2	^4.1.4

Runtime (server)

Package	From	To
dotenv	^17.4.0	^17.4.1

Engine & environment updates

• Node.js: >=24.13.0 → >=25.6.0 (root, server, vscode extension)
• VS Code: ^1.110.0 → ^1.115.0 (extension engines.vscode + @types/vscode)
• Devcontainer: typescript-node:24 → typescript-node:25
• .node-version: updated to 25.6.0

Notes

• No functional code changes; routine maintenance only.

[Copilot]

Pull request overview

Updates the repo’s Node.js toolchain baseline and bumps key Node/TypeScript linting/testing dependencies across the server and VS Code extension workspaces, aligning documentation and dev environments with the new minimum runtime.

Changes:

• Bump minimum Node.js version across packages/docs and update .node-version + devcontainer image.
• Upgrade common tooling (eslint, prettier, typescript-eslint) and test/type packages (vitest, @vitest/coverage-v8, @types/node, @types/vscode) in relevant workspaces.
• Patch-level update of dotenv in the server runtime dependencies.

Show a summary per file

File	Description
server/README.md	Updates server “Prerequisites” Node.js version to match the new minimum.
server/package.json	Raises Node engine requirement and bumps server deps/devDeps versions (incl. dotenv, lint/test tooling).
README.md	Updates repo-level environment prerequisites to Node.js v25.6.0+.
package.json	Raises root Node engine requirement and bumps shared dev tooling versions.
package-lock.json	Updates resolved versions/engines in lockfile to reflect dependency bumps.
extensions/vscode/README.md	Updates VS Code + Node.js prerequisites for the extension.
extensions/vscode/package.json	Updates engines (VS Code + Node) and bumps extension devDependencies (types/lint/test).
docs/public.md	Updates published minimum Node.js requirement and verification snippet.
docs/getting-started.md	Updates getting-started prerequisites Node.js version.
.node-version	Sets Node version file to v25.6.0 for tooling/CI.
.devcontainer/devcontainer.json	Moves devcontainer base image from Node 24 to Node 25.

Copilot's findings

• Files reviewed: 10/11 changed files
• Comments generated: 1