Print multi-line git errors readably #49

Since #30, a fatal git error other than "not a git repository" is reported with git's own message. For the most common case, a repository git refuses to trust, git's message spans several lines and ends with the fix (git config --global --add safe.directory …). codeheat escapes every control character in that message for the terminal, so the user sees one line full of \u000a and \u0009, and the hint is hard to read.

The escaping is deliberate: untrusted text (paths, git output) must not start new lines or recolor the terminal (apps/cli/src/output/escape.ts).

Idea: print git's stderr line by line, escaping each line on its own, with a fixed indent, so newlines come from codeheat and not from the untrusted text. Tabs could become spaces.

Done when: the dubious-ownership failure prints git's lines readably (journey test with GIT_TEST_ASSUME_DIFFERENT_OWNER=1), control characters inside a line are still escaped, and no other error message changes.