refactor(tui): extract shared setting edit overlay

[ericcurtin]

Summary

The `draw_edit_overlay` function in `sandbox_settings.rs` and `global_settings.rs` was nearly identical — the only difference was which settings slice the entry was resolved from (`app.sandbox_settings` vs `app.global_settings`).

Extract the common rendering logic into a single `draw_setting_edit_overlay` function in `ui/mod.rs`, parameterized by `key`, `kind`, `edit`, `area`, and `theme`. Each pane now resolves its own entry and delegates to the shared implementation.

Related Issue

N/A — identified via codebase duplication audit.

Changes

• Added `draw_setting_edit_overlay` to `ui/mod.rs` taking `(key, kind, edit, area, theme)` as parameters
• Replaced the ~38-line duplicate bodies in `sandbox_settings.rs` and `global_settings.rs` with 4-line delegating wrappers
• Added required `Clear`, `Padding` widget imports and `SettingEditState`, `Theme` type imports to `ui/mod.rs`

Net diff: -75 lines, +61 lines across the three files.

Testing

• `cargo check -p openshell-tui` passes
• `cargo clippy --workspace --all-targets -- -D warnings` passes (no new warnings)
• `cargo test -p openshell-tui` passes (22 tests, 0 failures)
• `cargo fmt --all -- --check` passes
• License header check passes
• E2E tests added/updated (not applicable — UI rendering only)

Checklist

• Follows Conventional Commits
• Commits are signed off (DCO)

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[russellb]

agent review:

No actionable findings.

I reviewed NVIDIA/OpenShell#1776 as a code review. The refactor preserves the existing behavior: both settings panes already aliased centered_popup as centered_rect, so the shared helper’s direct centered_popup(50, ...) call is equivalent. The parent-module private helper is accessible from child modules, and SettingValueKind is Copy, so the delegated calls compile cleanly.

I also tested it manually and both affected code paths still look fine in the TUI.

lgtm.

[TaylorMutch]

/ok to test baf8eb4