The gitea-pages push step used ${GITHUB_SHA::8}, a bash-only substring
expansion. The Gitea runner executes run: blocks with /bin/sh (dash),
which rejects it with "Bad substitution" and exits 2, failing the job
after the site had already built successfully.
Use cut(1) to shorten the SHA instead, which is POSIX sh compatible.
bun is already baked into the jellytau-builder image (Dockerfile.builder),
so oven-sh/setup-bun@v1 was redundant. Fetching that GitHub-hosted action
from the self-hosted Gitea runner hangs the job before any steps run.
Removed from traceability-check, traceability, and publish-docs workflows;
build-and-test and build-release never used it and never stalled.
Add a docs-site (mdBook) with a Gitea publish-docs workflow, a
release-notes generator script (release:notes) that turns a commit
range's TRACES into grouped notes, the background-audio feature spec,
and CLAUDE.md. Ignore docs-site build artifacts.