fix: lower minimum VS Code version to 1.94.0 - #1832

The current ^1.110.0 engine requirement prevents installation on older compatible editors, including OpenVSCode Server 1.103.1 described in discussion #1801. Lower engines.vscode to ^1.94.0, the earliest published VS Code release that passed the complete current VS Code test suites in the compatibility sweep following the language-client upgrade (#1831). Align @types/vscode to ~1.94.0 and update the lockfile so compilation targets the supported API and VSIX packaging accepts the lower engine requirement.

Compatibility evidence

The sweep tested the same source tree now on main (accfacf2ebb167210f5776a2e722760f18c38d4d; tree-identical to the tested upgrade commit b523f589b0682193eb0344d1e7340ff4faeff3cc). It used macOS arm64, R 4.6.1, R languageserver 0.3.20 and arf 0.5.3, with a fresh private profile for each run.

Every published release from the language client's 1.91.0 floor through 1.93.1 was tested. All failed first at Run Selection can create a persistent Interactive session and ordinary R exit leaves a restored notice, which timed out waiting for the stopped-session notebook notice after q("no"). The test passed alone on 1.91.1 but failed in its complete run; several subsequent 1.93.0 failures cascaded from Interactive timeouts. Thus 1.94.0 is the baseline validated by the current full suite, rather than proof of an inherent 1.94 API requirement.

The published vscode-languageclient 10.1.2 package enforces VS Code 1.91.0, and R Syntax 0.1.4 declares 1.90.0, both below the proposed baseline. VS Code 1.94.0 uses bundled Node 20.16.0 / Electron 30.5.1; the test that launches the actual host runtime without standalone Node on PATH passed.

Validation

• On this branch with the permanent ^1.94.0 manifest: all 391 extension tests and 2 isolated installer tests passed on VS Code 1.94.0, with normal timeouts, no bail, no retries, no test changes and no skips.
• Typecheck and lint passed after installing @types/vscode 1.94.0. Source and dependency declarations also passed checking with skipLibCheck disabled.
• Production VSIX packaging and packaged sess source-identity verification passed.
• The same source tree passed 116 Node tests, 1,246 sess R assertions, six source/bootstrap tests plus R identity/installer checks, lint, build and VSIX identity verification.

VS Code desktop 1.103.1 passed all 393 VS Code tests, supporting removal of the 1.110.0 installation barrier raised in #1801. These compatibility runs were on macOS desktop; the actual OpenVSCode Server environment and VS Code 1.94.0 on Linux/Windows have not been validated. The merged upgrade's existing CI passed on all three OSes with its configured test versions.

Detailed investigation · Discussion follow-up