v0.6.0

Changelog

• 2e16c7d build: add Makefile for common development tasks (#66)
• b671cd6 feat(cache): TTL-aware cache tracker for batch workloads (#61)
• c4455b8 feat(commits): semantic commit analysis with risk scoring (#64)
• 1c67071 feat(embedding): multi-provider abstraction layer (#62)
• 85cf702 feat(graph): code change impact graph with blast-radius queries (#65)
• 903b339 feat(logging): structured slog logger with JSON/text output (#67)
• 677ae8f feat(summarize): hierarchical multi-level conversation summarization (#63)