Avoid panic in file drop target QueryInterface

[warp-agent-staging]

Avoids panicking across the COM/FFI boundary when Windows calls the file drop target's QueryInterface. Sentry fatal WARP-CLIENT-BETA-STABLE-8C07 occurred when an injected Island DLP hook reached the existing unimplemented!().

This change matches upstream rust-windowing/winit#4571: it logs a warning and returns E_FAIL. It is based on Warp's maintained warpdotdev/v0.30.x branch and leaves file drag behavior unchanged outside interface queries that previously aborted the process.

Validation

• cargo check --target x86_64-pc-windows-gnu --lib

• RUSTFLAGS='--codegen=debuginfo=0 --deny=warnings' cargo build --target x86_64-pc-windows-gnu

• git diff --check

• cargo clippy --target x86_64-pc-windows-gnu --lib -- -D warnings is blocked by three existing clippy::incompatible_msrv errors in unchanged src/platform_impl/windows/util.rs.

• cargo +nightly fmt completed; unrelated formatting in unchanged event_loop.rs was reverted.

• Tested on all platforms changed — Windows GNU cross-target checks passed; native Windows/MSVC runtime validation remains for CI or reviewer testing.

• Added an entry to the changelog module if knowledge of this change could be valuable to users — no API or workflow change.

• Updated documentation to reflect any user-facing changes, including notes of platform-specific behavior — no public API or documented behavior changed.

• Created or updated an example program if it would help users understand this functionality — not applicable to this FFI failure-path fix.

Addresses fatal issue 7750551209 and event 6a1874f230e841c8ba0cd1ca9ec3957e.

[warp-agent-staging]

This PR was generated with Warp.

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