SPV: Killing dash-evo-tool during initial sync causes panics on restart

[lklimek]

Summary:
Killing dash-evo-tool during initial sync in debug builds causes a panic on restart. This does not occur with release builds.

Steps to Reproduce:

1. Start a debug build of dash-evo-tool at commit 7d1b8a361a8a3c7049525b891869523b63aa7738.
2. Kill the process during the initial sync.
3. Restart the tool.

Observed Behavior:

• The tool panics on startup after being killed during initial sync (debug build only).
• Release builds work as expected and do not panic on restart.

Stacktrace:

__rustc::rust_panic (@__rustc::rust_panic:6)
std::panicking::panic_with_hook (@std::panicking::panic_with_hook:70)
std::panicking::panic_handler::{{closure}} (@std::panicking::panic_handler::{{closure}}:43)
std::sys::backtrace::__rust_end_short_backtrace (@55555fddae79..55555fddaee1:3)
__rustc::rust_begin_unwind (@55555fdbdc9d..55555fdbdcff:3)
core::panicking::panic_fmt (@<*const T as core::fmt::Debug>::fmt:3)
dash_spv::storage::segments::SegmentCache<I>::get_items::{{closure}} (/home/lklimek/.cargo/git/checkouts/rust-dashcore-c6b13647c01f74b9/12ba186/dash-spv/src/storage/segments.rs:253)
<dash_spv::storage::block_headers::PersistentBlockHeaderStorage as dash_spv::storage::PersistentStorage>::open::{{closure}} (/home/lklimek/.cargo/git/checkouts/rust-dashcore-c6b13647c01f74b9/12ba186/dash-spv/src/storage/block_headers.rs:122)
<core::pin::Pin<P> as core::future::future::Future>::poll (/home/lklimek/.rustup/toolchains/1.92-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/future/future.rs:133)
dash_spv::storage::DiskStorageManager::new::{{closure}} (/home/lklimek/.cargo/git/checkouts/rust-dashcore-c6b13647c01f74b9/12ba186/dash-spv/src/storage/mod.rs:140)
dash_evo_tool::spv::manager::SpvManager::build_client::{{closure}} (/home/lklimek/git/dashevo/dash-evo-tool/src/spv/manager.rs:1396)
dash_evo_tool::spv::manager::SpvManager::run_spv_loop::{{closure}} (/home/lklimek/git/dashevo/dash-evo-tool/src/spv/manager.rs:857)
dash_evo_tool::spv::manager::SpvManager::start::{{closure}}::{{closure}} (/home/lklimek/git/dashevo/dash-evo-tool/src/spv/manager.rs:449)
<core::pin::Pin<P> as core::future::future::Future>::poll (/home/lklimek/.rustup/toolchains/1.92-x86_64-unknown-linux-gnu/lib/rustlib/src/future/future.rs:133)
tokio::runtime::park::CachedParkThread::block_on::{{closure}} (/home/lklimek/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.49.0/src/runtime/park.rs:284)
tokio::task::coop::with_budget (/home/lklimek/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.49.0/src/task/coop/mod.rs:167)
tokio::task::coop::budget (/home/lklimek/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.49.0/src/task/coop/mod.rs:133)
tokio::runtime::park::CachedParkThread::block_on (/home/lklimek/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.49.0/src/runtime/park.rs:284)
tokio::runtime::context::blocking::BlockingRegionGuard::block_on (/home/lklimek/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.49.0/src/runtime/context/blocking.rs:66)
tokio::runtime::scheduler::multi_thread::MultiThread::block_on::{{closure}} (/home/lklimek/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.49.0/src/runtime/scheduler/multi_thread/mod.rs:89)

Additional Notes:

• Affects only debug builds; release builds restart without panicking.
• Stacktrace points to segment/block header storage in dash-spv.
• May indicate missing error handling or state recovery on abrupt shutdown.
• Possibly related: feat: validate stored data on startup #398

Environment:

• dash-evo-tool commit: 7d1b8a361a8a3c7049525b891869523b63aa7738
• Platform: Linux (rustc 1.92, debug)
• dash-spv revision: 12ba186 (via .cargo/git/checkouts)

Impact:

• Developer/CI usability: restarting after a crash requires manual cleanup.
• Could mask underlying data corruption or error handling issue in SPV storage.

Expected Behavior:

• After a kill during sync, startup should handle storage/segment recovery gracefully in both debug and release builds; panics should be avoided.