parity(#244): normalize path separators in resolve_chunk so find_related works on Windows

[amondnet]

Summary

Upstream semble #244 (b491200) fixed find_related on Windows: resolve_chunk now normalizes \ → / on both the incoming file_path and each chunk's stored path before comparing. csp compares paths verbatim, so on Windows a file_path copied from a search result (or typed with the other separator) can fail to resolve.

Upstream

file_path = file_path.replace("\\", "/")
for chunk in chunks:
    if chunk.file_path.replace("\\", "/") == file_path and chunk.start_line <= line <= chunk.end_line:

csp status

• crates/csp/src/utils.rs::resolve_chunk: chunk.file_path == file_path exact match. Not reflected.
• csp stores chunk paths via Path::strip_prefix(display_root).to_string_lossy() (indexing/create.rs), i.e. the platform-native separator — same situation as upstream.
• csp ships Windows binaries (x86_64-pc-windows-msvc in release-rust.yml), so this is reachable.

Tasks

• Normalize separators in resolve_chunk (both sides), keeping the existing end-line fallback behavior.
• Unit test: backslash input resolves a forward-slash chunk and vice versa.

Refs

• Upstream: fix: Fix Windows console issues MinishLab/semble#244 (b491200)
• Sync baseline check: 949559b..6bbbd32, 2026-09-03