fix: keep rescue task calls in foreground

[lttlin]

Problem

codex:codex-rescue can orphan Codex runs in worktree isolation when the rescue agent backgrounds its single task Bash call. Claude Code cleans up the temporary worktree as soon as the agent returns, leaving Codex running in a deleted directory.

Root Cause

The rescue forwarding instructions still allow backgrounding the inner codex-companion.mjs task ... Bash call, and the command-contract tests do not enforce that the inner task must always run in the foreground.

Fix

Update the rescue agent and runtime skill to require foreground execution for the inner task Bash call in all cases. --background and --wait remain outer Claude-side controls, but they no longer authorize run_in_background: true on the inner task invocation.

Validation

• node --test --test-name-pattern='rescue command absorbs continue semantics|internal docs use task terminology' tests/commands.test.mjs
• Note: node --test tests/commands.test.mjs still has an unrelated pre-existing failure in the result and cancel commands are exposed as deterministic runtime entrypoints assertion on main

Closes #198