stat: shell-escape control chars in %N output (#9925)

[jamesarch]

Closes #9925.

Problem

GNU stat encodes control characters in file names using bash
`$'\X'` shell-escape sequences in the `%N` directive:

```
$ touch $'/tmp/test\nnewline'
$ /usr/bin/stat -c '{"name":"%N"}' $'/tmp/test\nnewline'
{"name":"'/tmp/test'$'\n''newline'"}
```

uutils was emitting the newline byte literally between single quotes,
producing invalid shell-quoted output and breaking JSON / log consumers
that parse the result:

```
{"name":"'/tmp/test
newline'"}
```

Fix

Delegate the quoting in stat::quote_file_name to uucore's shell-escape
implementation (uucore::quoting_style::locale_aware_escape_name),
which already handles control characters correctly. The local
QuotingStyle enum stays — it's still used to parse the
QUOTING_STYLE env var — but the actual escape work now flows through
uucore. Same code path that ls --quoting-style=shell-escape uses, so
stat -c %N output is now consistent with ls.

Cargo.toml: enables the quoting-style uucore feature for uu_stat.

Side effect

QUOTING_STYLE=locale on a file named exactly `'` now emits `"'"`
(matching ls and GNU's locale style in the C locale) instead of the
previous custom `'\''`. test_quoting_style_locale updated to
reflect this; the change makes stat's behavior consistent with the
other utilities.

Tests

Added:

• `test_format_n_handles_newline` — exact GNU output for newline.
• `test_format_n_handles_tab` — tab sanity check.

Updated:

• `test_quoting_style_locale` — see side-effect note above.

$ cargo test --features 'stat' --test tests -- test_stat
test result: ok. 35 passed; 0 failed

🤖 Generated with Claude Code

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/stat/stat-fmt. tests/stat/stat-fmt is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/date/date-locale-hour (fails in this run but passes in the 'main' branch)
Congrats! The gnu test tests/cut/cut-huge-range is now passing!
Congrats! The gnu test tests/rm/many-dir-entries-vs-OOM is now passing!