jpdev v0.4.0

jpdev v0.4.0

The turnaround rules move into the kit (#14, pull request #15).

What it holds

• templates/AGENTS.md (and the generated CLAUDE.md) gain the section "Before you hand over": the self-checks a builder runs on its own head before the commit message (the boundary paths unchanged, every schema member carried by a vector, both languages agreeing on shared vectors, every mutation row caught, every refusal event valid on malformed input, resumed runs carrying new checkpoint members, the design's words matching the code), the check list run with --only while iterating and whole once, shared paths changed by appending only while a sibling build is open, and the severity line.
• dev.json gains the optional handover object: boundary_paths and shared_paths. jpdev check prints one line with the counts of both when they are set.
• templates/codex-brief.md gains the section ## Before you write msg.txt. jpdev codex check-brief --build refuses a build brief without that heading; jpdev codex run uses the --build form.
• jpdev codex run exports the sandbox's scratch, lock and cache paths under the clone for the Codex process (JPDEV_SCRATCH, JPDEV_LOCK, GOCACHE, GOFLAGS=-mod=readonly, npm_config_cache, XDG_CACHE_HOME), each only when it is not already set, creates the directories, and refuses an --add that names one of them.
• docs/policy.md gains the "Turnaround" section: two builds on sibling branches, the coordinator carrying main, the builder's self-checks, the review re-read tier, CI green before any review. docs/adopting.md says what handover means for a builder.

What it does not hold

jpdev codex review (#13), the identifier exemption in the word list (#12), and the handover files staged through --add of a containing directory (#16). The repositories that vendor the pair re-vendor it after this release.