fix: clean unrecorded rollback snapshots

[shakkernerd]

Summary

• remove a failed rollback safety snapshot when state restoration succeeded but history persistence failed
• retain safety snapshots when history records them or restoration itself failed
• report removed snapshots accurately across pretty, raw, and JSON output

Verification

• reproduced the orphaned-snapshot failure on AWS before the fix
• AWS Crabbox: cargo test --locked
• AWS Crabbox: cargo check --locked --all-targets
• AWS Crabbox: cargo check --locked --target x86_64-pc-windows-gnu
• AWS Crabbox: all explicit rollback tests plus exact-tip lifecycle and render tests
• cargo fmt --check
• git diff --check

[shakkernerd]

Merged using rebase.

What changed after review:

• Removed unrecorded safety snapshots after failed rollback attempts that successfully restored the pre-rollback state.
• Retained recorded snapshots and snapshots needed after failed restoration.
• Corrected pretty, raw, and JSON reporting for removed safety snapshots.

Verification:

• Reproduced the orphaned-snapshot failure on AWS before the fix.
• AWS Crabbox cbx_a55a7013c2d7: full cargo test --locked, all-target checks, and Windows GNU compile passed.
• Explicit rollback lifecycle tests and exact-tip rendering tests passed.
• Auto-review: history, snapshot, recovery, cleanup-error, and output branches reviewed clean.
• GitHub checks: all required checks green on the prepared head.

Landed on main:

• Final landed SHA: 8a5c563; range 3a76b99...8a5c563.

Thanks @shakkernerd!