v0.12.3

Changes

• Fix token accounting: Include cache_creation_input_tokens in context fill formula — all three input token types (input_tokens, cache_creation_input_tokens, cache_read_input_tokens) are separate per Anthropic API docs
• Fix cache %: Include cache_creation_input_tokens in denominator for accurate cache efficiency display
• Rename api → wait: The API time ratio metric now shows as wait X% for clearer semantics (measures time spent waiting for API responses vs total session time)
• Fix session cross-pollution: Cache file is now scoped per session_id so independent Claude Code instances (e.g. Prism + terminal) don't overwrite each other's data
• Updated website demo, landing page, and README to match