Bump version to v0.2.1

Improve DSL ergonomics with imported context helpers

Update README for v0.2.0 APIs

Release v0.2.0

Add server DSL, pubsub integration, and typed LSP helpers

chore: commit user changes

feat: improve transport, router ergonomics, state modes, and type coercion

docs: update README and add agent completion rules

ci: upload built hex tarball as workflow artifact

docs: add changelog and license extras for ex_doc

build: include ex_doc dev dependency for docs task

ci: use dep-based ex_doc instead of archive install

ci: split validation and release workflows; harden docs step

ci: run docs in dev env and fetch per-env deps

ci: run test/docs/build and publish on main pushes