v0.13.6

[0.13.6] — 2026-07-06

Declare @reactive-agents/runtime-shim as a dependency of the CLI and mark it
external in the bundle. The rax serve command imports secureServe from it;
previously it was inlined into the CLI bundle instead of resolved from
node_modules. Functionally identical for users, but restores the deduplicated
external-dependency packaging the other workspace deps use.

Bump plan shortId() entropy from 4 to 6 base36 characters. The 4-char id space
(~1.7M) made a 100-id uniqueness draw collide roughly 0.3% of the time — a real
intermittent CI failure in the plan tests. Six characters (~2.2B) makes it
effectively never, and the id stays within its 8-character budget (p_ + 6).