fix(server): keep installed editors visible when discovery times out

[eeinarsson]

What Changed

• made Windows editor discovery bounded and concurrent while preserving partial successes
• retained last-known editors when a discovery attempt is incomplete
• added an optional completion signal and one retry through the existing config snapshot stream
• added focused shell, launcher, server, and picker coverage

Why

Editor discovery could exceed the server config timeout and discard editors already found, causing clients to incorrectly show “No installed editors found.”

The optional completion field and existing snapshot event keep this compatible across mixed client/server versions.

Fixes #4697.

Related approaches: #4739 and #4435. Complementary command-probe performance work: #4778.

UI Changes

Before:

After:

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• No animation or interaction changes require a video

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Note

Medium Risk
Changes editor discovery, caching, and server config contract; behavior is well covered by tests but affects cross-platform PATH probing and WebSocket config snapshots.

Overview
Editor discovery could exceed the server config timeout and drop editors already found, so the UI showed “No installed editors found” even when VS Code (etc.) was installed.

Shared shell layer adds discoverAvailableCommands, which probes commands with bounded concurrency and a timeout and returns { available, complete }. On Windows it scans PATH directories concurrently instead of serial per-editor checks.

External launcher now returns EditorDiscoveryResult (editors + complete), caches successful discovery for one minute, merges partial results with the last-known list on timeout, and shares one in-flight lookup across callers (including after interrupt or defect).

Server config exposes optional availableEditorsComplete on ServerConfig. subscribeServerConfig emits a follow-up snapshot one second later when the first discovery was incomplete so clients can refresh without blocking the initial response.

Web UI (OpenInPicker) uses that flag so an empty menu shows “Couldn’t check for installed editors” when discovery is incomplete or unknown, and “No installed editors found” only after a complete empty scan.

^{Reviewed by Cursor Bugbot for commit e6f1eb2. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Keep installed editors visible in the UI when editor discovery times out

• Adds discoverAvailableCommands in shell.ts to probe editor availability concurrently with a bounded timeout, returning partial results and a complete flag on timeout.
• Rewrites resolveAvailableEditors in externalLauncher.ts to return { editors, complete }, with a 3s discovery timeout, 1-minute TTL cache for complete results, and shared in-flight deduplication across concurrent callers.
• Propagates availableEditorsComplete through the server config contract and WebSocket handlers; subscribeServerConfig emits a second snapshot after 1s when the initial discovery was incomplete.
• Updates OpenInPicker.tsx to show "Couldn't check for installed editors" instead of "No installed editors found" when discovery did not complete.
• Behavioral Change: serverGetConfig responses now include availableEditorsComplete; incomplete first discoveries are not cached, causing a retry on the next request.

^{Macroscope summarized e6f1eb2.}

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[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

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[macroscopeapp]

Approvability

Verdict: Needs human review

This PR introduces significant new functionality: timeout-aware editor discovery with caching, retry logic, and a new API field (availableEditorsComplete). The complex concurrency patterns (semaphores, deferreds, shared discovery) and new runtime behavior warrant human review despite comprehensive test coverage.

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[macroscopeapp]

One finding on Effect dependency acquisition: the new Windows discovery path reads process.env directly instead of the HostProcessEnvironment reference already used elsewhere in this module.

^{Posted via Macroscope — Effect Service Conventions}