[cherry-pick] nes: fix: normalize Windows workspace path casing

[vs-code-engineering]

Cherry-pick of #333429 from main.

Fixes #325491

Root cause

NES creates its document ID from doc.uri.toString(). On Windows, URI serialization lowercases the drive letter, producing /c:/workspace/..., while the workspace-folder URI can retain /C:/workspace. toUniquePath compared these paths case-sensitively, failed to strip the workspace root, and leaked an absolute drive path into the Lysithea prompt and speculative prediction.

The first native Windows CI run reproduced this exactly:

Expected: "space folder/test.py:"
Received: "/c:/workspace/space folder/test.py:"

Fix

• Normalize only the Windows drive-letter segment before workspace-root comparison.
• Preserve case-sensitive semantics for every other path segment, including virtual notebook providers.
• Cover file-backed notebook cells with fragment retention and case-sensitive virtual notebook cells.
• Make response coverage assert progressive reveal, which requires correct active-document matching.

Validation

• Initial native Windows CI reproduced the absolute-path leak.
• Refined fix passed Copilot - Test (Windows).
• All actual PR CI checks passed.
• Targeted Xtab tests: 267 passed, 4 Windows-only tests skipped on macOS.
• ESLint passed for all changed files.

The draft-only VS Code PR Check policy remains pending.

[Copilot]

Pull request overview

Fixes Windows NES path matching by normalizing drive-letter casing while preserving other path casing.

Changes:

• Normalize Windows drive letters during workspace-relative path comparison.
• Preserve notebook fragments and virtual-path case sensitivity.
• Add Windows coverage for prompts, notebooks, and progressive patch reveal.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
promptCraftingUtils.ts	Normalizes drive-letter casing for relative paths.
xtabProvider.spec.ts	Tests Windows and notebook path handling.
xtabPatchResponseHandler.spec.ts	Tests progressive edits for Windows paths with spaces.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[github-actions]

Screenshot Changes

Base: 5c917327 Current: 7a44938e

Changed (1)

chat/aiCustomizations/aiCustomizationManagementEditor/McpServersSearch/Light

Before	After

1 insignificant change(s) omitted (≤20 px, Δ≤2). See CI logs for details.

[Vritant Bhardwaj (vritant24)]

Ulugbek Abdullaev (@ulugbekna) since we are now past endgame, does this need to still be taken in this release or can this flow into next week's release?