Bumps the desktop version from 0.0.12 to 0.0.13, so Sparkle offers a new canary built from current `main` (26351c0) plus this bump. Nate asked for this release.

Included since 0.0.12: - #111: worktree channels are grouped under their repository's project. - #114: the streaming reply draft renders inside the timeline instead of over it. - #112: checkout development runs are isolated from installed helpers; development builds can be signed with a local Git identity setting.

Validation: `bun types` and `bun run ci` pass on this lane. The signed **Desktop release** workflow with publishing enabled is running on bd2406a: https://github.com/githubnext/ace2/actions/runs/37356991538. It notarizes the app and DMG and verifies the public download bytes before publishing the signed canary feed.

### Built in Ace

An Ace channel (canary-release) did all Git and GitHub work, checks, and the release dispatch through its shell tool. No other tools were used. Workaround: the `lane` tool created the lane from the project checkout's stale `feat/github-cache` HEAD, so the agent reset the lane to `origin/main` (#96).