main fixes: write schema budget, Copy lint, Unix-scoped test imports, /cost fixture

Shortens file tool descriptions and reuses the line_ending schema in WriteTool
(#7070), copies InteractionTarget, scopes test-only imports in app-server, and
updates the /cost [details] diagnostics fixture (requires_argument now true).

Verified: tools::file 191/191, frame:: 37/37, surface_metadata 1/1. app-server
changes are compile-checked only by the in-progress CLI build.

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>

crates/app-server/src/bridge.rs

@@ -17,7 +17,7 @@ use std::process::{Command, Stdio};
 use std::sync::Arc;
 use std::time::Duration;
 use tokio::io::AsyncWrite;
-#[cfg(test)]
+#[cfg(all(test, unix))]
 use tokio::sync::Mutex;
 
 /// Historical cold-child cache comparator. It has no production producer.

crates/app-server/src/lib.rs

@@ -18,7 +18,9 @@ use std::collections::HashMap;
 use std::net::SocketAddr;
 use std::path::{Path, PathBuf};
 #[cfg(test)]
-use std::process::{Child, Command};
+use std::process::Child;
+#[cfg(all(test, unix))]
+use std::process::Command;
 use std::sync::Arc;
 use std::time::Duration;
 use tokio::io::{AsyncBufRead, AsyncWrite, BufReader};

crates/tui/src/commands/fixtures/diagnostics/surface_metadata.txt

@@ -10,10 +10,10 @@ show_in_empty_discovery: true
 ---
 name: cost
 aliases: []
-usage: /cost
+usage: /cost [details]
 description_en: Show session cost breakdown
 palette_en: Show session cost breakdown
-requires_argument: false
+requires_argument: true
 unlisted: false
 show_in_empty_discovery: true
 ---

crates/tui/src/tools/file.rs

@@ -113,7 +113,7 @@ fn verify_expected_hash(
 /// The hidden compatibility schema still has a byte budget, so this is only the
 /// instruction the legacy caller needs: what to pass and what happens on a
 /// mismatch. The rationale stays in doc comments rather than schema bytes.
-pub(super) const EXPECTED_HASH_DESCRIPTION: &str = "The `content_hash` from a prior read; the write is refused and the file left unchanged if it changed since";
+pub(super) const EXPECTED_HASH_DESCRIPTION: &str = "Prior read's content_hash; refuse the write if the file has changed.";
 
 // === Cross-harness parameter aliases ===
 
@@ -1021,7 +1021,7 @@ impl ToolSpec for ReadFileTool {
             "properties": {
                 "path": {
                     "type": "string",
-                    "description": "Path to the file (relative to workspace, absolute, or ~/ home-relative). Alias: `file_path`"
+                    "description": "File path: workspace-relative, absolute or ~/. Alias: file_path"
                 },
                 "start_line": {
                     "type": "integer",
@@ -1029,11 +1029,11 @@ impl ToolSpec for ReadFileTool {
                 },
                 "max_lines": {
                     "type": "integer",
-                    "description": "Maximum lines to return (default 500, max 500; a 16KB byte budget applies regardless). Aliases: `limit`, `n_lines`"
+                    "description": "Lines: default/max 500, also capped at 16KB. Aliases: limit, n_lines"
                 },
                 "pages": {
                     "type": "string",
-                    "description": "PDF only: page range to extract, e.g. \"1-5\" or \"10\". Ignored for non-PDF files."
+                    "description": "PDF page range, e.g. 1-5 or 10; ignored for other files."
                 }
             },
             "required": ["path"]
@@ -1702,7 +1702,7 @@ impl ToolSpec for WriteFileTool {
                 "line_ending": {
                     "type": "string",
                     "enum": ["preserve", "lf", "crlf"],
-                    "description": "Line endings to use: preserve existing style by default, or set lf or crlf when explicitly requested. Explicit selection converts CRLF and lone CR to the requested style."
+                    "description": "Default: preserve existing endings. Explicit lf/crlf converts CRLF and lone CR."
                 }
             },
             "required": ["path", "content"]

crates/tui/src/tools/file_tool.rs

@@ -126,6 +126,7 @@ impl ToolSpec for WriteTool {
     }
 
     fn input_schema(&self) -> Value {
+        let write = WriteFileTool.input_schema();
         json!({
             "type": "object",
             "properties": {
@@ -134,11 +135,7 @@ impl ToolSpec for WriteTool {
                     "description": "Path to the file to write (relative or absolute)."
                 },
                 "content": { "type": "string", "description": "Content to write to the file." },
-                "line_ending": {
-                    "type": "string",
-                    "enum": ["preserve", "lf", "crlf"],
-                    "description": "Preserve the existing style by default. Use lf or crlf when explicitly requested; CRLF and lone CR are converted to the selected style."
-                }
+                "line_ending": write["properties"]["line_ending"]
             },
             "required": ["path", "content"],
             "additionalProperties": false

crates/tui/src/tui/ui/frame.rs

@@ -3178,13 +3178,12 @@ mod tests {
         assert!(rendered.contains("checkout"), "{rendered}");
         assert!(rendered.contains("feature-6112"), "{rendered}");
         assert!(rendered.contains("v9.9.9"), "{rendered}");
-        let target = app
+        let target = *app
             .viewport
             .interaction_targets
             .iter()
             .find(|target| target.id == crate::tui::tideline::InteractionTargetId::HEADER_UPDATE)
-            .expect("visible update notice is actionable")
-            .clone();
+            .expect("visible update notice is actionable");
         assert_eq!(
             target.mouse_action,
             Some(crate::tui::tideline::InteractionAction::OpenUpdate)