[M10] Validate LSP client compatibility, responsiveness, and workspace behavior

[Teakowa]

Parent: #27

Depends on: #64, #67

Planning status: settled by the #75 contract — true in-flight cancellation is
deferred; stale-result suppression is the M10 requirement.

Goal

Validate Wright's language services through real protocol/client workflows and ensure responsiveness/project behavior is acceptable without editor-specific extensions.

Scope

• Exercise the LSP server with multiple standards-compliant client/test harnesses where practical.
• Validate open/change/save/close, multi-file includes/projects, diagnostics refresh, navigation, completion, rename, and semantic tokens.
• Measure interactive latency and memory on representative projects.
• Test rapid edits, stale-version suppression, workspace reload, and error recovery. In-flight request cancellation is explicitly deferred (see [M10 planning] Reconcile cancellation and responsive-analysis contracts #75) and is not an M10 requirement.
• Verify behavior does not depend on a Wright-owned VS Code/browser extension.
• Add regression cases for protocol/client interoperability issues discovered during validation.

Non-goals

• Maintaining editor-specific UI plugins.
• Optimizing beyond measured responsiveness bottlenecks.
• Validating speculative in-flight cancellation infrastructure ([M10 planning] Reconcile cancellation and responsive-analysis contracts #75).

Acceptance criteria

• Supported language features work through standard LSP interactions in representative clients/harnesses.
• Interactive latency/resource behavior is measured and acceptable for the declared project scale.
• Rapid edits do not surface stale semantic results as current. This is distinct from in-flight request cancellation, which is explicitly deferred per [M10 planning] Reconcile cancellation and responsive-analysis contracts #75.
• Workspace/project behavior matches Wright CLI/toolchain source resolution.

[Teakowa]

Delivered in commit 7b0d0f2 (crates/wright-lsp/tests/lsp.rs).

• An end-to-end protocol harness drives the real wright-lsp binary over stdio: initialize capability negotiation, didOpen→publishDiagnostics, hover/definition/references/completion, rename (previewed workspace edit), semanticTokens/full, didChange with version bump (stale-version suppression), and shutdown/exit.
• Malformed input produces structured diagnostics without a crash; document versions are tracked and stale results replaced (tested).

[Teakowa]

Remediated and re-verified (commits c4fc954..c8c17b2).

The real wright-lsp protocol harness now covers: capability negotiation, didOpen/didChange/didClose with client versions, stale/out-of-order suppression, rename edit application and refusal, cross-file definition/references, filesystem and unsaved-overlay includes, workspace root from initialize, rapid consecutive edits, malformed input, UTF-16 non-BMP positions, and bounded round-trip latency (20 requests).