## Why
The Linux sandbox represents missing protected metadata paths such as `.git`
with empty read-only directories. Repository and project discovery treated any
`.git` directory as a checkout root, so this synthetic directory could hide a
real parent repository and its trust configuration.
## What changed
- Treat a `.git` directory as repository metadata only when it contains
`HEAD`, while continuing to recognize file-based `.git` entries.
- Protect missing `.git` paths with the same read-only synthetic mounts as
other workspace metadata without disrupting parent-repository discovery.
- Canonicalize and read-only bind the synthetic-mount registry into the
sandbox, and make protected-path cleanup handle read-only directory trees.
## Testing
Added coverage for repository, project-root, trust, synthetic-mount, and
Landlock behavior, including nested incomplete `.git` directories and a
redirected `TMPDIR`.
GitOrigin-RevId: 0724c54d56531143bb28011e4ca414cd3b0212be
## What changed
- Include legacy managed-file and MDM settings when resolving project root markers and project trust in both canonical and executor-local config loads.
- Preserve the existing managed-layer precedence in the final config stack and resolve managed relative paths against the same bases used by the final loader.
- Update explicit-untrusted warnings to describe the effective configuration and direct users to an administrator when the setting is managed.
## Testing
- Cover managed root markers, managed trust overrides, MDM precedence, app-server config reads, and the remote TUI warning.
GitOrigin-RevId: 9b5ddd54b4530f73589d6842a15cbab7e6d6bbb9
## What changed
- Query the remote app server for project config layers before starting a thread and show the trust prompt when the project has no existing decision.
- Resolve relative remote working directories and repository-root trust targets, then persist accepted trust through `config/batchWrite` on the remote server.
- Preserve existing trusted and untrusted decisions, including an untrusted repository that contains the requested working directory.
- Exit when the remote trust prompt is declined and ignore repeated key events in the trust selector.
## Testing
- Add coverage for remote trust detection, persistence, thread startup, existing decisions, nested untrusted projects, and rendering a remote Git subdirectory.
GitOrigin-RevId: e5fba2ea23bad1fb28f01df522cadbe05fcbb942
## Summary
TUI config writes currently wrap app-server failures with local context
like `config/batchWrite failed in TUI`, but several user-visible paths
only render the outer error. That hides the actionable app-server
message, such as validation constraints or read-only `CODEX_HOME`
failures, leaving users with a dead-end diagnostic.
This change adds a small formatter next to the TUI config write helpers
that renders the error source chain, then uses it for model persistence,
feature persistence, project trust, status line writes, hook trust, and
hook enablement.
Fixes#26077
Eric Traut