fix: stabilize release changelog generation (#19987)

.opencode/command/changelog.md

@@ -2,22 +2,43 @@
 model: opencode/kimi-k2.5
 ---
 
-create UPCOMING_CHANGELOG.md
+Create `UPCOMING_CHANGELOG.md` from the structured changelog input below.
+If `UPCOMING_CHANGELOG.md` already exists, ignore its current contents completely.
+Do not preserve, merge, or reuse text from the existing file.
 
-it should have sections
+Any command arguments are passed directly to `bun script/changelog.ts`.
+Use `--from` / `-f` and `--to` / `-t` to preview a specific release range.
 
-```
-## TUI
+The input already contains the exact commit range since the last non-draft release.
+The commits are already filtered to the release-relevant packages and grouped into
+the release sections. Do not fetch GitHub releases, PRs, or build your own commit list.
+The input may also include a `## Community Contributors Input` section.
 
-## Desktop
+Before writing any entry you keep, inspect the real diff with
+`git show --stat --format='' <hash>` or `git show --format='' <hash>` so the
+summary reflects the actual user-facing change and not just the commit message.
+Do not use `git log` or author metadata when deciding attribution.
 
-## Core
+Rules:
 
-## Misc
-```
+- Write the final file with sections in this order:
+  `## Core`, `## TUI`, `## Desktop`, `## SDK`, `## Extensions`
+- Only include sections that have at least one notable entry
+- Keep one bullet per commit you keep
+- Skip commits that are entirely internal, CI, tests, refactors, or otherwise not user-facing
+- Start each bullet with a capital letter
+- Prefer what changed for users over what code changed internally
+- Do not copy raw commit prefixes like `fix:` or `feat:` or trailing PR numbers like `(#123)`
+- Community attribution is deterministic: only preserve an existing `(@username)` suffix from the changelog input
+- If an input bullet has no `(@username)` suffix, do not add one
+- Never add a new `(@username)` suffix from `git show`, commit authors, names, or email addresses
+- If no notable entries remain and there is no contributor block, write exactly `No notable changes.`
+- If no notable entries remain but there is a contributor block, omit all release sections and return only the contributor block
+- If the input contains `## Community Contributors Input`, append the block below that heading to the end of the final file verbatim
+- Do not add, remove, rewrite, or reorder contributor names or commit titles in that block
+- Do not derive the thank-you section from the main summary bullets
+- Do not include the heading `## Community Contributors Input` in the final file
 
-fetch the latest github release for this repository to determine the last release version.
+## Changelog Input
 
-find each PR that was merged since the last release
-
-for each PR spawn a subagent to summarize what the PR was about. focus on user facing changes. if it was entirely internal or code related you can ignore it. also skip docs updates. each subagent should append its summary to UPCOMING_CHANGELOG.md into the appropriate section.
+!`bun script/changelog.ts $ARGUMENTS`