fix(changelog): restore history eroded by the path filter

[Ripwords]

Recovers the changelog history that filter_changelog_by_paths had been deleting on every release, and stops it leaving empty headings behind.

Found while testing the release-tooling refactor (#7): releasing from a clone and diffing the result showed CHANGELOG.md | 504 +-------- — 490 deletions.

What was happening

The filter ran over the whole file with a keep-set covering only FROM..HEAD, so every previously-released entry's bullets referenced SHAs outside the range and were dropped. Each release eroded a little more. The ## headings survived (no [sha] to match), so the file kept looking plausible while draining.

Entry	at sdk-v0.4.0	before this PR
sdk-v0.4.0	257 bullets	2
sdk-v0.3.0	107 bullets	1
sdk-v0.2.1	4 bullets	1

That gutted file ships in the npm tarball and gets pasted into each GitHub Release. The cause is fixed in #7; this restores the data.

Restored

File	before	after
packages/core/CHANGELOG.md	9 bullets	65
apps/extension/CHANGELOG.md	8 bullets	205
packages/expo/CHANGELOG.md	7 bullets	29

Root CHANGELOG.md was never filtered — untouched.

Not a verbatim restore, deliberately

Each entry is recovered from its own tag's copy, where it was still intact. But sdk-v0.3.0 and sdk-v0.4.0 predate the filter — b1bb22c landed 15 minutes after sdk-v0.4.0 — so their sections were never scoped and carry dashboard-only commits. Restoring those as-is would trade one wrong changelog for another.

So every recovered section gets the scoping rule applied retroactively: a bullet survives only if its commit touched that artifact's paths in that tag's range. The result is what each release would have written had the filter existed and worked. For sdk-v0.4.1/0.4.2 it's a no-op.

Nothing is invented — every line comes from the file as it existed at that tag; the only edit is dropping out-of-scope bullets. Bullets labelled dashboard: that genuinely touched packages/shared (e.g. 368d63b) are kept on purpose: the rule is paths, not the commit's scope label.

One deliberate difference: expo is scoped to packages/{expo,sdk-utils,shared}. The old release-expo.sh also passed packages/recorder, which expo doesn't depend on.

Empty subsections (separate commit)

The filter dropped bullets but left their ### heading, which carries no [sha] to match on — packages/core/CHANGELOG.md shipped 14 of 38 subsections empty (### 🏡 Chore with nothing under it). Subsections are now buffered and emitted only if a bullet survived. After: 0 empty across all three files.

Verification

Unit-tested the rewritten filter against a fixture, covering all five behaviours at once:

Behaviour	Result
In-scope bullet	kept ✅
Out-of-scope bullets	dropped ✅
Subsection whose bullets all dropped	heading removed too ✅
### ❤️ Contributors (bullet, no sha)	kept ✅
Historical section, sha outside range	preserved ✅

And on the restored files: every version heading present, every bullet count up, 0 empty subsections.

Already-published npm tarballs keep their eroded copy — this fixes the repo and every future publish.

🤖 Generated with Claude Code