[P4suta]

Why

Local Git and shell inspection can fail before reporting a policy decision or can reject valid preparation commands.
These boundary errors interrupt scoped issue work and initial imports.

Changes

• Refuse Git metadata writes before worktree-only queries.
• Report unsupported wrappers as named command refusals and isolate each PowerShell parser cache.
• Accept regular-expression dollar anchors while keeping unclosed parameter expansions blocked.
• Resolve Git remote names and explicit GitHub owner/name values for repository descriptions.
• Detect missing versioned ignore files before enumerating local selection paths.
• Ignore deleted selection source objects during initial import while keeping live history, signing, and one-time import checks.

Validation

Each defect has a regression that fails before its fix.
mise x -- just check --base origin/main passed for the implementation with an isolated verification cache in XDG_CACHE_HOME.
The final documentation change passes the selected prose gate.
The gate includes Clippy, workspace tests, structural checks, profile checks, dependencies, secrets, and prose.
The runtime installer and just install-pr-workflow install the affected binaries.
The release proof campaigns remain unrun.

Closes #458.

@coderabbitai ignore