no-mistakes v1.15.0 adds intent extraction

Hot take: this is the right kind of “major” update for an agentic devtool, because validation is only as good as the context it can preserve.

• –Intent extraction is the real feature here; it turns no-mistakes from a diff checker into a context-aware gate.
• –PR intent sections should make review output easier to read and easier to trust when multiple agents or rebases are involved.
• –The orphaned base SHA fix is a practical signal that the team is working through the messy edge cases that break real-world automation.
• –Inference: this should reduce noisy validation results when the code change is mechanically fine but semantically diverges from the original plan.