release: v0.4.0 Refined Semolina

[nullhack]

Release v0.4.0 — Refined Semolina

Added

• CLI flow name resolution: short flow names resolved from .flowr/flows/; --flows-dir global flag; FlowNameNotFoundError
• Session management: session init/show/set-state/list, --session flag on transition/next/check, --format yaml|json, subflow push/pop, atomic writes, session path resolution
• Configurable paths: flowr config subcommand with source provenance (default / pyproject.toml / cli)
• README rewrite: clear purpose, audience, show-don't-tell examples, architecture section
• Documentation portal: role-based docs/index.html

Changed

• FlowNameNotFoundError (was FlowNameNotFound) per PEP 8
• --flows-dir moved from per-subcommand to global flag
• Exit code 1 for flow not found (was 2)
• SessionStore Protocol in domain layer (hexagonal architecture)
• 100% test coverage across all modules

Versioning

• Bumps to semver 0.4.0 (previous format 0.3.20260427 was non-standard)
• Changelog heading uses v0.4.0+20260502 format per versioning convention
• check_version.py updated to accept +date build metadata in headings