Remove ghost snapshots (#19481)

## Summary
- Remove `ghost_snapshot` / `GhostCommit` from the Responses API surface
and generated SDK/schema artifacts.
- Keep legacy config loading compatible, but make undo a no-op that
reports the feature is unavailable.
- Clean up core history, compaction, telemetry, rollout, and tests to
stop carrying ghost snapshot items.

## Testing
- Unit tests passed for `codex-protocol`, `codex-core` targeted undo and
compaction flows, `codex-rollout`, and `codex-app-server-protocol`.
- Regenerated config and app-server schemas plus Python SDK artifacts
and verified they match the checked-in outputs.

codex-rs/git-utils/src/lib.rs

@@ -2,7 +2,6 @@ mod apply;
 mod baseline;
 mod branch;
 mod errors;
-mod ghost_commits;
 mod info;
 mod operations;
 mod platform;
@@ -20,21 +19,8 @@ pub use baseline::diff_since_latest_init;
 pub use baseline::ensure_git_baseline_repository;
 pub use baseline::reset_git_repository;
 pub use branch::merge_base_with_head;
-pub use codex_protocol::models::GhostCommit;
 pub use codex_protocol::protocol::GitSha;
 pub use errors::GitToolingError;
-pub use ghost_commits::CreateGhostCommitOptions;
-pub use ghost_commits::GhostSnapshotConfig;
-pub use ghost_commits::GhostSnapshotReport;
-pub use ghost_commits::IgnoredUntrackedFile;
-pub use ghost_commits::LargeUntrackedDir;
-pub use ghost_commits::RestoreGhostCommitOptions;
-pub use ghost_commits::capture_ghost_snapshot_report;
-pub use ghost_commits::create_ghost_commit;
-pub use ghost_commits::create_ghost_commit_with_report;
-pub use ghost_commits::restore_ghost_commit;
-pub use ghost_commits::restore_ghost_commit_with_options;
-pub use ghost_commits::restore_to_commit;
 pub use info::CommitLogEntry;
 pub use info::GitDiffToRemote;
 pub use info::GitInfo;

codex-rs/git-utils/src/operations.rs

@@ -1,6 +1,5 @@
 use std::ffi::OsStr;
 use std::ffi::OsString;
-use std::path::Component;
 use std::path::Path;
 use std::path::PathBuf;
 use std::process::Command;
@@ -45,38 +44,6 @@ pub(crate) fn resolve_head(path: &Path) -> Result<Option<String>, GitToolingErro
     }
 }
 
-pub(crate) fn normalize_relative_path(path: &Path) -> Result<PathBuf, GitToolingError> {
-    let mut result = PathBuf::new();
-    let mut saw_component = false;
-    for component in path.components() {
-        saw_component = true;
-        match component {
-            Component::Normal(part) => result.push(part),
-            Component::CurDir => {}
-            Component::ParentDir => {
-                if !result.pop() {
-                    return Err(GitToolingError::PathEscapesRepository {
-                        path: path.to_path_buf(),
-                    });
-                }
-            }
-            Component::RootDir | Component::Prefix(_) => {
-                return Err(GitToolingError::NonRelativePath {
-                    path: path.to_path_buf(),
-                });
-            }
-        }
-    }
-
-    if !saw_component {
-        return Err(GitToolingError::NonRelativePath {
-            path: path.to_path_buf(),
-        });
-    }
-
-    Ok(result)
-}
-
 pub(crate) fn resolve_repository_root(path: &Path) -> Result<PathBuf, GitToolingError> {
     let root = run_git_for_stdout(
         path,
@@ -89,47 +56,6 @@ pub(crate) fn resolve_repository_root(path: &Path) -> Result<PathBuf, GitTooling
     Ok(PathBuf::from(root))
 }
 
-pub(crate) fn apply_repo_prefix_to_force_include(
-    prefix: Option<&Path>,
-    paths: &[PathBuf],
-) -> Vec<PathBuf> {
-    if paths.is_empty() {
-        return Vec::new();
-    }
-
-    match prefix {
-        Some(prefix) => paths.iter().map(|path| prefix.join(path)).collect(),
-        None => paths.to_vec(),
-    }
-}
-
-pub(crate) fn repo_subdir(repo_root: &Path, repo_path: &Path) -> Option<PathBuf> {
-    if repo_root == repo_path {
-        return None;
-    }
-
-    repo_path
-        .strip_prefix(repo_root)
-        .ok()
-        .and_then(non_empty_path)
-        .or_else(|| {
-            let repo_root_canon = repo_root.canonicalize().ok()?;
-            let repo_path_canon = repo_path.canonicalize().ok()?;
-            repo_path_canon
-                .strip_prefix(&repo_root_canon)
-                .ok()
-                .and_then(non_empty_path)
-        })
-}
-
-fn non_empty_path(path: &Path) -> Option<PathBuf> {
-    if path.as_os_str().is_empty() {
-        None
-    } else {
-        Some(path.to_path_buf())
-    }
-}
-
 pub(crate) fn run_git_for_status<I, S>(
     dir: &Path,
     args: I,
@@ -161,27 +87,6 @@ where
         })
 }
 
-/// Executes `git` and returns the full stdout without trimming so callers
-/// can parse delimiter-sensitive output, propagating UTF-8 errors with context.
-pub(crate) fn run_git_for_stdout_all<I, S>(
-    dir: &Path,
-    args: I,
-    env: Option<&[(OsString, OsString)]>,
-) -> Result<String, GitToolingError>
-where
-    I: IntoIterator<Item = S>,
-    S: AsRef<OsStr>,
-{
-    // Keep the raw stdout untouched so callers can parse delimiter-sensitive
-    // output (e.g. NUL-separated paths) without trimming artefacts.
-    let run = run_git(dir, args, env)?;
-    // Propagate UTF-8 conversion failures with the command context for debugging.
-    String::from_utf8(run.output.stdout).map_err(|source| GitToolingError::GitOutputUtf8 {
-        command: run.command,
-        source,
-    })
-}
-
 fn run_git<I, S>(
     dir: &Path,
     args: I,