Keep delegated workspace clone logs out of user-facing failure details

[codeforester]

Goal

Keep timestamped delegated Base log records out of the user-facing failure-detail block rendered by basectl workspace clone.

Background

workspace clone now renders failures beneath the repository/action/result row. Its clone_detail() helper currently concatenates the delegated basectl repo clone stderr and stdout verbatim. When the child emits a timestamped logger line such as ... ERROR subcommands/repo.sh:2179 ..., that internal log record is treated as ordinary detail and receives table indentation. The result is visually misleading and makes the failure block harder to scan.

Scope

• Filter timestamped Base logger records from normal workspace-clone failure details.
• Preserve actionable child diagnostics such as authentication guidance and provider responses.
• Keep complete delegated stdout/stderr available through debug logging or the existing command log path.
• Add regression coverage for mixed diagnostic output and logger lines.
• Update the workspace clone output documentation if needed.

Acceptance Criteria

• A failed delegated clone does not render timestamped DEBUG, INFO, WARN, or ERROR records as indented user-facing detail.
• The result row remains aligned and actionable, including provider errors, recovery guidance, and exit codes.
• Existing clone, optional-repository, dry-run, redaction, return-code, and aggregate-summary behavior remains unchanged.
• Raw delegated output remains available through the debug/diagnostic path.
• Focused workspace tests, git diff --check, and the full Base validation gate pass.

Validation

• Add a regression fixture containing a provider diagnostic, recovery guidance, a timestamped Base logger record, and ordinary stdout.
• Assert the actionable diagnostics remain visible and the timestamped logger record is absent from normal output.
• Run focused workspace-clone and repository-URL tests.
• Run the workspace BATS tests.
• Run ./bin/base-test with the documented writable cache/source environment.
• Run git diff --check.

Non-Goals

• Do not change clone authentication or GitHub API behavior.
• Do not change the delegated basectl repo clone command or logger format.
• Do not redesign the workspace result table or add a machine-readable format.
• Do not suppress provider diagnostics needed for recovery.

Project Fields

• Status: In Progress
• Priority: P2
• Area: Workspace
• Initiative: Workspace Handling
• Size: S
• Milestone: v1.9.0

Agent Assignment

Implement in one canonical issue worktree, keep the change limited to clone failure-detail normalization, and open a linked PR after validation.