Fix execpolicy parsing for multiline quoted args (#9565)

## What
Fix bash command parsing to accept double-quoted strings that contain
literal newlines so execpolicy can match allow rules.

## Why
Allow rules like [git, commit] should still match when commit messages
include a newline in a quoted argument; the parser currently rejects
these strings and falls back to the outer shell invocation.

## How
- Validate double-quoted strings by ensuring all named children are
string_content and then stripping the outer quotes from the raw node
text so embedded newlines are preserved.
- Reuse the helper for concatenated arguments.
- Ensure large SI suffix formatting uses the caller-provided locale
formatter for grouping.
- Add coverage for newline-containing quoted arguments.

Fixes #9541.

## Tests
- cargo test -p codex-core
- just fix -p codex-core
- cargo test -p codex-protocol
- just fix -p codex-protocol
- cargo test --all-features

codex-rs/protocol/src/num_format.rs

@@ -28,6 +28,10 @@ pub fn format_with_separators(n: i64) -> String {
     formatter().format(&Decimal::from(n)).to_string()
 }
 
+fn format_with_separators_with_formatter(n: i64, formatter: &DecimalFormatter) -> String {
+    formatter.format(&Decimal::from(n)).to_string()
+}
+
 fn format_si_suffix_with_formatter(n: i64, formatter: &DecimalFormatter) -> String {
     let n = n.max(0);
     if n < 1000 {
@@ -58,7 +62,7 @@ fn format_si_suffix_with_formatter(n: i64, formatter: &DecimalFormatter) -> Stri
     // Above 1000G, keep whole‑G precision.
     format!(
         "{}G",
-        format_with_separators(((n as f64) / 1e9).round() as i64)
+        format_with_separators_with_formatter(((n as f64) / 1e9).round() as i64, formatter)
     )
 }