Moves the Atomic harness to 0.9.29.

## What changes

- `package.json`: the `harness` catalog moves `@bastani/atomic` from `0.9.28` to `0.9.29`. - `bun.lock`: `@bastani/atomic`, `@bastani/atomic-natives` and `@bastani/pi-ai` move to 0.9.29. Atomic's `@earendil-works` packages stay at 1.1.0; nothing else in the lockfile changes. - `docs/self-hosting.md` names 0.9.29. - 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`: 4407 pass, 3 skip, 0 fail (with `GIT_CONFIG_GLOBAL=/dev/null`, as in #420). - `bun run types`: all workspace checks pass. - `bun run ci`: dprint, oxlint, tokens, design contract, design record and Impeccable pass, with no new findings. - Not run: Playwright e2e or a live Planner session.

Assistant-workflow: inline Assistant-duration: 4m converged, estimated 20m Assistant-verification: bun test passed: 4407 pass, 3 skips, 0 fail (GIT_CONFIG_GLOBAL=/dev/null) Assistant-verification: bun run types passed: all workspace checks Assistant-verification: bun run ci passed: no new findings Assistant-verification: source check passed: Atomic 0.9.29 builtins unchanged User-preference: Keep pdd-kit and Chopin on the same Atomic release, with transitive deps upgraded together Co-authored-by: Alex Lavaee <lavaman131@github.com>