v0.3.0

Changelog

• a9b98fd feat(cli): hcli prune retention command; stricter config loading
• 22ca51b feat(tui): sparkline stretches sparse data; range-aware labels; height-aware cost view
• 61cf325 fix(collect): OTLP/HTTP conformance for the receiver
• 1958a82 fix(store): store all timestamps as canonical UTC text
• aa76423 fix(tui): display-width-aware cell truncation; drop dead root flags
• 897dfae fix(tui): overview stat cards no longer clip the last border
• aca15ec refactor(cli): every command resolves config/db through one path