fix(tools): keep tool labels workspace-relative on Windows

crates/host-core/src/tools/mod.rs

@@ -16,7 +16,7 @@ use tokio::io::{AsyncRead, AsyncReadExt};
 use tokio::process::{ChildStderr, ChildStdin, ChildStdout, Command};
 use tokio::sync::{mpsc, watch};
 
-use crate::workspace::{resolve_tool_path_with_external, ToolRoot};
+use crate::workspace::{resolve_tool_path_with_external, simple_canonicalize, ToolRoot};
 
 mod grep_rg;
 pub mod hashline;
@@ -2625,7 +2625,13 @@ fn relative_display(root: &Path, path: &Path) -> String {
     // `path` comes back canonicalized from the resolver; strip against the
     // canonical root spelling too, or symlinked roots (macOS /var vs
     // /private/var) would render absolute.
-    let canonical_root = root.canonicalize().unwrap_or_else(|_| root.to_path_buf());
+    //
+    // The resolver spells paths with `simple_canonicalize`, so the root must
+    // use that same spelling: std `Path::canonicalize` keeps the Windows
+    // `\\?\` prefix, which never matches a resolved path and made every
+    // workspace-relative label fall back to an absolute one.
+    let canonical_root =
+        simple_canonicalize(root).unwrap_or_else(|_| root.to_path_buf());
     path.strip_prefix(&canonical_root)
         .or_else(|_| path.strip_prefix(root))
         .unwrap_or(path)

crates/host-core/src/workspace.rs

@@ -4,7 +4,12 @@ use std::path::{Component, Path, PathBuf};
 /// Canonicalize a path, stripping the Windows extended-length prefix (`\\?\`)
 /// when the result is a simple drive-letter path (e.g. `C:\...`). This keeps
 /// paths compatible with shell APIs (`ShellExecuteW`) that reject `\\?\`.
-fn simple_canonicalize(path: &Path) -> std::io::Result<PathBuf> {
+///
+/// Every path the resolver returns carries this spelling, so any caller that
+/// compares a resolved path against a root must canonicalize that root the
+/// same way — std `Path::canonicalize` keeps the `\\?\` prefix on Windows and
+/// would never match.
+pub(crate) fn simple_canonicalize(path: &Path) -> std::io::Result<PathBuf> {
     let canonical = path.canonicalize()?;
     #[cfg(windows)]
     {

docs/spec/06-delivery/04-e2e-test-plan.md

@@ -1394,7 +1394,11 @@ Each scenario is documented in this format:
 - **Acceptance**: E (bounded cross-platform search)
 - **Milestone**: M5
 - **Status**: Unit-covered (host-core and agent-runtime); live multi-platform
-  protocol capture pending
+  protocol capture pending. The workspace-relative path expectation is covered
+  on Windows by `relative_display`, which must canonicalize the workspace root
+  with the resolver's own spelling (`simple_canonicalize`) — std
+  `Path::canonicalize` keeps the `\\?\` prefix there and silently degrades
+  every label to an absolute path.
 
 #### E2E-019a: Scratch-directory writes stay out of the workspace (D114)
 

docs/zh-CN/spec/06-delivery/04-e2e-test-plan.md

@@ -800,7 +800,11 @@ M5。
 - **接受**：E（有界跨平台搜索）
 - **里程碑**：M5
 - **状态**：单元覆盖（host-core 和代理运行时）；多平台直播
-  协议捕获待处理
+  协议捕获待处理。工作区相对路径这一预期在 Windows 上由
+  `relative_display` 覆盖：它必须用解析器自身的拼写
+  （`simple_canonicalize`）规范化工作区根目录——标准库
+  `Path::canonicalize` 在 Windows 上会保留 `\\?\` 前缀，从而把所有标签
+  静默降级为绝对路径。
 
 #### E2E-019a：暂存目录写入不在工作区中 (D114)