fix(cursor_desktop): support write/edit tools and normalize workspace matching

[Adityakk9031]

Summary

Adds Write and Edit tool support to Cursor Desktop conversions, and normalizes workspace folder paths in workspace_id_for on Windows and Unix.

Motivation & Context

1. normalize_tool and denormalize_tool in cursor_desktop.rs only supported terminal and read tools (run_terminal_command_v2 and read_file_v2), leaving Write and Edit tool calls unhandled. This caused converted Cursor Desktop drafts to fall back to Tool::Raw without capability numbers (capability 43 for write, 44 for edit).
2. workspace_id_for compared stripped file:// URI paths directly against cwd without decoding percent-encoded characters (like %3A for :) or normalizing path separators and casing. On Windows, this caused workspace matching to always fail and file sessions under an "empty-window" workspace instead of their project workspace.

Changes

• Added write_file_v2 (capability 43) and edit_file_v2 (capability 44) in normalize_tool and denormalize_tool.
• Added matches_workspace_folder and normalize_path to handle decoded percent-encodings and slash normalization across platforms.

[NishantJoshi00]

@perry-the-agent can you review this?

[perry-the-agent]

Found one blocking correctness issue in workspace matching. I reviewed the exact head SHA 94ecf142e9636248b37c9d8574a4c2cd9899f789. Local validation passed: cargo test --all-features, cargo test -p txcript --all-features, cargo fmt --all -- --check, cargo clippy -p txcript --all-features --all-targets -- -D warnings, and git diff --check. The current GitHub checks are also green.

[perry-the-agent]

@NishantJoshi00 reviewed the current head (94ecf142e9636248b37c9d8574a4c2cd9899f789) and requested changes. The review found three correctness issues: incomplete file-URI decoding (blocking), silent loss of Edit.replace_all, and POSIX absolute/relative paths being treated as equal. Primary review: #24 (review). Independent follow-up: #24 (review)

[perry-the-agent]

Two additional correctness findings from an independent review pass:

[perry-the-agent]

Agent session: https://skillsync.com/nishantjosh/t/gkWS9EB4xa

[Adityakk9031]

@perry-the-agent Thanks for the review!

Addressed all three findings in commit c1b660e:

1. [P1] File URI percent decoding: Added ile_uri_to_path and hex_pair to decode full percent-encoded paths (including spaces like %20, Unicode like %C3%A9), with graceful passthrough for invalid % sequences.
2. [P2] Preserve
   eplace_all: Restricted the native edit_file_v2 arm to Tool::Edit { replace_all: false, .. }, so edits with
   eplace_all: true fall through to the generic canonical representation and roundtrip losslessly. Added fixpoint regression test edit_tool_with_replace_all_survives_fixpoint.
3. [P3] Preserve POSIX path roots: Updated path normalization to preserve leading root slashes on non-Windows platforms while removing only the URI-added leading slash for Windows drive-letter paths (/C: -> C:). Added negative tests ensuring /repo does not match
   epo.

[NishantJoshi00]

Please fix these before merging:

1. Preserve Cursor's edit fields, including relativeWorkspacePath and contentsAfterEdit. Keep the original call raw if it can't be mapped without losing data.
2. Remove IDs 43/44 from the Write/Edit mappings. They mean Create Plan and List MCP Resources. Use a verified native format or keep the existing fallback.
3. Only replace backslashes with slashes on Windows.
4. Add tests using Cursor's native schema. Check that edit parameters survive conversion and exported tool IDs match Cursor's definitions.

[Adityakk9031]

Thanks for the review and corrections @NishantJoshi00! I have addressed all 4 points in the latest commit:

1. Preserve Cursor's native edit fields:

   • In normalize_tool, we now verify that parameters strictly match the standard 3-field schema (targetFile, oldString, newString) without extra metadata before converting to canonical Tool::Edit.
   • When Cursor provides native edit metadata like relativeWorkspacePath and contentsAfterEdit, the call is preserved as Tool::Raw with all original JSON keys intact, ensuring zero data loss across conversions. A similar check was applied for write_file_v2.

2. Remove incorrect tool IDs 43 and 44:

   • Removed IDs 43 and 44 from write_file_v2 and edit_file_v2 in denormalize_tool. They now export with number: None (preserving existing fallback behavior) rather than emitting misleading capability IDs (CreatePlan / ListMcpResources).

3. Platform-scoped backslash replacement:

   • In normalize_path, backslash-to-slash replacement is now strictly scoped to Windows (if is_windows). On POSIX/Unix systems, backslashes are preserved as legal filename characters.

4. Added native schema and definition tests:

   • Added cursor_native_edit_with_extra_fields_survives_conversion_and_has_no_invalid_tool_id to verify that edits with contentsAfterEdit and relativeWorkspacePath survive conversion losslessly as Tool::Raw and export without invalid tool IDs.
   • Added exported_tool_ids_match_cursor_definitions verifying Cursor tool numbers:
     • Terminal (15), Read (40), Ripgrep (41), Glob (42), Ask (51)
     • Write and Edit do not emit 43/44 (number: None).
   • Added POSIX unit tests verifying backslashes are preserved on non-Windows.

The workspace matching and replace_all issues are fixed and covered by regression tests.