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/1.17.2.md

@@ -0,0 +1,42 @@
+---
+version: 1.17.2
+date: 2026-08-01
+---
+
+## App
+
+### New
+- **Desktop/Windows:** added Windows ARM64 support (thanks to @airtaxi).
+- UI: a new OpenChamber theme (dark and light) is now the default, replacing the previous default theme.
+- Sessions: a root session can now be moved with all its sub-sessions into a new worktree directly from the header menu.
+- Desktop/Linux: added a Window Controls Style setting to switch between classic rectangular buttons and macOS-style traffic lights (thanks to @kydorn).
+- Files: added a global Auto-save setting under Settings → General; binary, PDF, and Office files are excluded from auto-save (thanks to @makeittech).
+
+### Improvements
+- Desktop: the active session header now has a menu with rename, share, export, archive, delete, and copy-ID actions; share links copy to the clipboard automatically when created.
+- Git/Diff: symlinks now appear as link entries in the diff view instead of showing their file content.
+- Sidebar: sessions with active agents now show a live activity indicator even when the sidebar is collapsed (thanks to @pascalandr).
+- VSCode: per-session permission auto-accept now replies to live permission requests correctly when auto-accept is turned on.
+- Usage: all Z.ai usage windows now appear in the usage view.
+- Chat: tool descriptions now show the glob pattern when a tool's input uses one.
+- Chat: clicking in the padding area of the composer now correctly places the cursor (thanks to @IbrahimKhan12).
+
+### Fixes
+- **Mobile:** rebuilt the app navigation around two swipe drawers — a sessions drawer (left) with a cross-project tree, swipe actions to rename, archive, or delete sessions, and a workspace drawer (right) with Changes, Files, Terminal, Notes, and MCP tabs. Tapping the session title in the header switches recents from a compact overlay with live status indicators. Cold launches reopen the last active session and land on an explicit connect screen on failure instead of flashing an empty draft.
+- Performance: opening the first session after startup is faster — background startup requests no longer queue ahead of the initial message load (thanks to @yulia-ivashko).
+- Terminal: switching terminal tabs no longer rebuilds the connection from scratch on each open or switch (thanks to @makeittech).
+- Desktop: sticky session headers in the sidebar no longer blink or shift position during page transitions (thanks to @ChangeHow).
+- Chat: the `/` command menu no longer lists a skill twice when a command shares its name (thanks to @IbrahimKhan12).
+
+## VS Code
+
+### Improvements
+- Per-session permission auto-accept now replies to live permission requests correctly when auto-accept is turned on.
+- Sessions with active agents now show a live activity indicator even when the sidebar is collapsed (thanks to @pascalandr).
+- Usage: all Z.ai usage windows now appear in the usage view.
+- Chat: tool descriptions now show the glob pattern when a tool's input uses one.
+- Chat: clicking in the padding area of the composer now correctly places the cursor (thanks to @IbrahimKhan12).
+
+### Fixes
+- Chat: messages arriving at the start of the SSE stream no longer drop silently after initial connection.
+- Chat: the `/` command menu no longer lists a skill twice when a command shares its name (thanks to @IbrahimKhan12).