Passive recording hooks for gaps the native records leave (from #2) #21

Split from #2, which shipped in v0.2.0 without this criterion: "Fill necessary recording gaps with bounded passive hooks where supported. Verify their actual delivery and expose capture failures." Agent Observer 0.2.0 reads only the records each harness already writes; agent-observer trace --capabilities lists what each adapter observes and what stays unknown (for example, Codex has no native skill-invocation event).

Acceptance criteria

• For each unknown family in the capability matrix that a harness can report through a supported hook, a bounded passive hook records it, with its delivery verified on this Mac.
• Capture failures are visible in health and the capability matrix.

🤖 Generated with Claude Code