feat: verify CLI protocol version on LS start [IDE-1652]

[nick-y-snyk]

Description

Adds verifyCliProtocolVersion() called from SnykLanguageServer.start() after the CLI path is validated. If the CLI reports a protocol version that doesn't match REQUIRED_LS_PROTOCOL_VERSION, the plugin logs and shows a user-visible error and aborts LS startup. Non-parseable output is treated as non-fatal (logged, startup continues).

Matches the equivalent gate added in VSCode extension PR #733. Part of IDE-1652.

Checklist

• Read and understood the Code of Conduct and Contributing Guidelines.
• Tests added and all succeed
• Linted
• CHANGELOG.md updated
• README.md updated, if user-facing

Screenshots / GIFs

N/A — no UI change.

[snyk-io]

✅ Snyk checks have passed. No issues have been found so far.

Status	Scan Engine	Critical	High	Medium	Low	Total (0)
✅	Open Source Security	0	0	0	0	0 issues
✅	Licenses	0	0	0	0	0 issues
✅	Code Security	0	0	0	0	0 issues

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[acke]

Would it be possible to add a smoke test that actually downloads a real Snyk CLI binary and exercises verifyCliProtocolVersion() against it end-to-end? The current tests stub the CLI with a temp shell script (and skip on Windows), so they don't catch the case where the real CLI's language-server --protocolVersion output format changes or the version-negotiation contract drifts between the plugin and the actual CLI release.

[snyk-pr-review-bot]

PR Reviewer Guide 🔍

🧪 PR contains tests

🔒 No security concerns identified

⚡ Recommended focus areas for review Indefinite Blocking 🟠 [major] The verifyCliProtocolVersion method calls proc.getInputStream().readAllBytes() before proc.waitFor(). Since readAllBytes() blocks until the stream is closed or EOF is reached, if the CLI process hangs or fails to close its output stream, the Language Server startup thread will block indefinitely. The 5-second timeout on waitFor is never reached in this scenario. Consider reading from the stream with a timeout or using the process's output after the timeout has been enforced. String output = new String(proc.getInputStream().readAllBytes(), StandardCharsets.UTF_8).trim(); proc.waitFor(5, TimeUnit.SECONDS);

📚 Repository Context Analyzed This review considered 8 relevant code sections from 7 files (average relevance: 0.79) plugin/src/main/java/io/snyk/eclipse/plugin/SnykStartup.java (lines 1-179) plugin/src/main/java/io/snyk/languageserver/protocolextension/SnykExtendedLanguageClient.java (2 segments, lines 1-108) plugin/src/main/java/io/snyk/languageserver/download/LsDownloader.java (lines 1-188) plugin/src/main/java/io/snyk/languageserver/LsRuntimeEnvironment.java (lines 1-194) plugin/src/main/java/io/snyk/languageserver/SnykLanguageServer.java (lines 1-153) plugin/src/main/java/io/snyk/eclipse/plugin/analytics/TaskProcessor.java (lines 1-78) plugin/src/main/java/io/snyk/eclipse/plugin/Activator.java (lines 1-97)