chore(agent-core-v2): drop speculative remote-runtime path mapping

The only runtime implementation today is local, whose mapRoots is the
identity — the remote relocation scenarios cannot occur yet. Keep the
lease-acquired filesystem read (correct locally too) and return snapshot
keys to plain host-relative resolution; the mapped-root translation
returns when a non-local runtime actually lands.

Author: user

packages/agent-core-v2/src/features/fileHistory/fileHistoryService.ts

@@ -134,9 +134,7 @@ export class AgentFileHistoryService extends Service implements IAgentFileHistor
       (c) => c.turnId === turnId && checkpointPhaseOf(c) === phase,
     );
     if (index < 0) return undefined;
-    const pathKey = this.pathKey(path);
-    if (pathKey === undefined) return undefined;
-    const entry = entryAt(state.checkpoints, index, pathKey);
+    const entry = entryAt(state.checkpoints, index, this.pathKey(path));
     if (entry === undefined) return undefined;
     if (entry.key === null) return { version: entry.version };
     const bytes = await this.blobs.get(this.agentCtx.scope(), entry.key);
@@ -163,7 +161,6 @@ export class AgentFileHistoryService extends Service implements IAgentFileHistor
 
   private async capture(path: string, turnId: number): Promise<void> {
     const pathKey = this.pathKey(path);
-    if (pathKey === undefined) return;
     const state = this.history();
     if (state.tracked.includes(pathKey)) return;
 
@@ -248,23 +245,11 @@ export class AgentFileHistoryService extends Service implements IAgentFileHistor
   }
 
   private async readCurrent(pathKey: string): Promise<Uint8Array | 'missing' | 'unreadable'> {
+    const absolute = isAbsolute(pathKey) ? pathKey : resolve(this.workspaceCtx.workDir, pathKey);
     const lease = this.runtime.acquire(['fs']);
     try {
       const fs = lease.runtime.fs;
       if (fs === undefined) return 'unreadable';
-      const runtime = lease.runtime;
-      const hostWorkDir = resolve(this.workspaceCtx.workDir);
-      const mappedWorkDir = runtime.path.resolve(
-        runtime.workspace.mapRoots({ workDir: this.workspaceCtx.workDir, additionalDirs: [] })
-          .workDir,
-      );
-      let absolute: string;
-      if (isAbsolute(pathKey)) {
-        if (mappedWorkDir !== hostWorkDir) return 'unreadable';
-        absolute = pathKey;
-      } else {
-        absolute = runtime.path.resolve(mappedWorkDir, pathKey);
-      }
       let info;
       try {
         info = await fs.stat(absolute);
@@ -283,37 +268,14 @@ export class AgentFileHistoryService extends Service implements IAgentFileHistor
     }
   }
 
-  private pathKey(path: string): string | undefined {
+  private pathKey(path: string): string {
     if (!isAbsolute(path)) return path;
-    const hostRelative = relative(resolve(this.workspaceCtx.workDir), path);
-    if (containedRelative(hostRelative)) return hostRelative;
-    const lease = this.runtime.acquire();
-    try {
-      const runtime = lease.runtime;
-      const mappedWorkDir = runtime.path.resolve(
-        runtime.workspace.mapRoots({ workDir: this.workspaceCtx.workDir, additionalDirs: [] })
-          .workDir,
-      );
-      if (mappedWorkDir === resolve(this.workspaceCtx.workDir)) return path;
-      const mappedRelative = runtime.path.relative(mappedWorkDir, path);
-      if (containedRelative(mappedRelative)) return mappedRelative.replaceAll('\\', '/');
-      return undefined;
-    } finally {
-      lease.dispose();
-    }
+    const relativePath = relative(this.workspaceCtx.workDir, path);
+    if (relativePath === '' || relativePath === '..' || relativePath.startsWith('../')) return path;
+    return relativePath;
   }
 }
 
-function containedRelative(relativePath: string): boolean {
-  return (
-    relativePath !== '' &&
-    relativePath !== '..' &&
-    !relativePath.startsWith('../') &&
-    !relativePath.startsWith('..\\') &&
-    !isAbsolute(relativePath)
-  );
-}
-
 function editTargetPath(display: ToolInputDisplay | undefined): string | undefined {
   if (display === undefined || display.kind !== 'file_io') return undefined;
   if (display.operation !== 'edit' && display.operation !== 'write') return undefined;