chore(release): unwrap CHANGELOG paragraphs for GitHub Release notes (#180)

GitHub renders release-note Markdown with GFM hard breaks, so every
`\n` becomes `<br>`. The CHANGELOG is hard-wrapped at ~75 chars for
readable diffs, which renders as awkward visible line breaks on the
release page (see https://github.com/colbymchenry/codegraph/releases/tag/v0.7.10).

Add `scripts/extract-release-notes.mjs` to extract a version block
and join indented continuation lines into a single line per bullet.
Nested list items, headings, and link references are preserved.
`scripts/release.sh` now uses this helper instead of the inline awk
extractor — repo-level CHANGELOG.md viewing is unaffected because
CommonMark there treats newlines as spaces.

Also fix the 0.7.10 entry: "Two underlying fixes" -> "Three", "Rust
file-/level" broken hyphen, and move the closes/credit line above
the nested list so it doesn't strand as a top-level paragraph.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/release.sh

@@ -30,13 +30,11 @@ if ! grep -q "^## \[${VERSION}\]" CHANGELOG.md; then
   exit 1
 fi
 
-NOTES=$(awk -v v="${VERSION}" '
-  /^## \[/ {
-    if (p) exit
-    if ($0 ~ "^## \\[" v "\\]") p = 1
-  }
-  p
-' CHANGELOG.md)
+# Extract notes with paragraph unwrapping — GitHub Releases render with
+# GFM hard-breaks, so the CHANGELOG's hard-wrapped lines would show as
+# visible `<br>` breaks otherwise. The helper joins continuation lines
+# into a single line per bullet.
+NOTES=$(node scripts/extract-release-notes.mjs "${VERSION}")
 
 if [ -z "${NOTES}" ]; then
   echo "error: failed to extract changelog notes for ${VERSION}" >&2