test(fuse): update INIT_EXT flag name expectation

[ligeng8848]

Summary

Update the FUSE INIT capability-name test to reflect that bit 30 is now registered as FUSE_INIT_EXT, while preserving coverage for the hexadecimal fallback of unmapped bits.

Issue Describe / Design

No related issue.

Root cause:
The test still treated bit 30 (0x40000000) as unknown, but the production capability-name map now registers that bit as INIT_EXT.

Reproduction:
cargo test -p curvine-fuse fuse_init_flag_names_maps_known_and_unknown --lib

Fix approach:
Assert that FUSE_INIT_EXT renders as INIT_EXT, and use bit 31 to verify the hexadecimal fallback for an unmapped bit.

Changes

Module / File	Change	Impact on existing behavior
curvine-fuse/src/fs/curvine_file_system.rs	Update the INIT flag-name test data and expectations	None; test-only change

Test verified

Test case	Result	Notes
cargo test -p curvine-fuse fuse_init_flag_names_maps_known_and_unknown --lib	PASS	1 passed
cargo test -p curvine-fuse init_ --lib	PASS	8 passed
cargo fmt --package curvine-fuse -- --check	PASS
cargo test -p curvine-fuse --lib	PARTIAL	333 passed; 5 unrelated permission/special-file tests failed independently
make format	BLOCKED	Full workspace clippy is blocked on local macOS by existing recursion-limit, RocksDB C++ header, and unrelated warning failures; the target file remains formatted

Dependencies

• Related PRs: None
• Related issues: None
• Blocks / blocked by: None

[szbr9486]

Reviewed the test update against the current FUSE INIT capability map and the unknown-bit fallback. I found no actionable code issues in this change.