feat(snapshot): report capture outcomes

[msmps]

Summary

• return an explicit immediate, changed, settled, deadline, or exited outcome with every snapshot
• preserve the latest screen on deadlines and final screen plus process metadata on exits
• add --strict exit categories: 3 for timing deadlines and 4 for ended sessions, without discarding evidence
• make snapshots protocol-v2 only, remove dual timeout behavior, and handle finalization races without transient SESSION_NOT_FOUND
• document outcome-driven agent behavior in the CLI help, READMEs, and packaged skill

Verification

• cargo fmt --all -- --check
• cargo clippy --all --benches --tests --examples --all-features -- -D warnings
• cargo test --workspace --all-features (227 passed, 1 ignored doc test)
• cargo build --workspace --all-features
• cargo build --workspace --release --all-features
• isolated daemon dogfood confirmed immediate, evidence-bearing deadline with exit 3 under --strict, and lifecycle exit 4