feat(changelog): one source file per release, generated outputs

Release notes now live in changelog/<version>.md (front matter with
version and date, then ## App and ## VS Code sections grouped into
New, Improvements, Fixes, Misc) plus changelog/unreleased.md for what
has not shipped. `bun run changelog:build` renders CHANGELOG.md,
packages/vscode/CHANGELOG.md, and changelog/index.json from them;
`changelog:check` fails when the outputs are behind and runs in CI and
in release:prepare. `oc-dev create-release` promotes unreleased.md to
the versioned file dated today and rebuilds.

The existing history was split mechanically: every bullet kept, sorted
into groups by keyword, five hand-typed headers with one-digit days
normalised to YYYY-MM-DD (the update dialog matched none of them). The
generated files keep today's release headers, which the update dialog,
the release workflow, and the website match by regex.

Claude-Session: https://claude.ai/code/session_01VqV56Hez25hTxXH4ipJfzH

changelog/1.9.7.md

@@ -0,0 +1,36 @@
+---
+version: 1.9.7
+date: 2026-04-22
+---
+
+## App
+
+### New
+- Desktop: added an Electron desktop runtime in parallel with the current Tauri app, with Electron planned to become the default path in an upcoming release.
+- Plans/Notes/Todos: added editable project plans from assistant messages, external plan upload, configurable planning magic prompts, and quicker note/todo handoff into new sessions or worktrees.
+- Chat/Files: you can now drag files and folders from the file tree into chat, with improved `@folder` autocomplete (thanks to @youfch).
+- Files/Git: added a file-change summary bar and auto-refresh for open files changed outside the app.
+
+### Improvements
+- Settings/MCP: improved MCP auth flow with better remote-config support and clearer diagnostics, and aligned config resolution with OpenCode behavior (thanks to @daveotero, @cyan).
+- Reliability/Chat: hardened bootstrap and stream-connection recovery, preserved session/connect state, and reduced streaming UI churn.
+
+### Fixes
+- Sessions/UI: added bulk session selection in the sidebar and fixed pinned sessions (thanks to @yart).
+- Git/Worktrees: improved branch/worktree reliability by allowing checkout with uncommitted changes, tightening worktree cache invalidation, and reducing incorrect remote prefetches (thanks to @jwcrystal, @jasonalsing).
+- Web/PWA: added install orientation controls and fixed loopback-origin handling for web push notifications in local setups (thanks to @vhqtvn, @yart).
+
+## VS Code
+
+### New
+- Chat/Files: you can now drag files and folders from the file tree into chat, with improved `@folder` autocomplete when building prompt context (thanks to @youfch).
+
+### Improvements
+- Files: open editors now refresh file content after external changes.
+- Settings/MCP: improved MCP auth flow with remote config support and clearer diagnostics (thanks to @daveotero).
+- Chat/Questions: single-choice questions now use radio selection.
+- Reliability: config resolution now matches OpenCode behavior more closely.
+- Reliability/Streaming: strengthened bootstrap and connection recovery paths.
+
+### Fixes
+- Sessions/UI: added bulk selection in the sessions sidebar and fixed pinned sessions (thanks to @yart).