Atomic 0.9.27 is out, and it's the stable release of 0.9.27-alpha.1, which the Planner already runs. Its changelog entries match the alpha's, so the Planner's behavior doesn't change. The lockfile does change: `@bastani/atomic-natives` 0.9.27 is published for every platform, so `bun.lock` regains the Windows entries that 0.9.27-alpha.1 lacked.

## What changes

- `package.json`: the `harness` catalog moves `@bastani/atomic` from `0.9.27-alpha.1` to `0.9.27`. - `bun.lock`: `@bastani/atomic`, `@bastani/atomic-natives` (now including `win32-arm64-msvc` and `win32-x64-msvc`), and `@bastani/pi-ai` move to 0.9.27. Atomic's `@earendil-works` packages stay at 1.0.2. - `docs/self-hosting.md`: names Atomic 0.9.27.

The five builtin packages (intercom, mcp, subagents, web-access, workflows) are unchanged, so `BUILTINS_OFF` still turns off each one for the isolated Planner.

## Verification

- `bun test`: 3666 pass, 3 skip, 0 fail. - `bun run types`: all workspace checks pass. - `bun run ci`: dprint, oxlint (0 errors), tokens, design contract, design record, and Impeccable pass, with no new findings. - Not run: a live Planner session on 0.9.27.

Assistant-workflow: inline Assistant-verification: bun test passed: 3666 pass, 3 skips, 0 fail Assistant-verification: bun run types passed: all workspace checks Assistant-verification: bun run ci passed: no new findings Assistant-verification: source check passed: @bastani/atomic 0.9.27 dist/builtin lists intercom, mcp, subagents, web-access, workflows; changelog entries match 0.9.27-alpha.1 Co-authored-by: Alex Lavaee <lavaman131@github.com>