fix: preserve SELinux hook resources and bound panic logs

[JavSaia]

Disabling SELinux hiding currently unhooks and frees original-call trampolines and a status page that can still be executing or mapped by an application. Keep the five handler hooks and their original-call trampolines resident until reboot; disabling switches each handler back to the original implementation. Serialize enable/disable attempts and reuse partial successful installations on retry.

Remove the fallback that overwrites write_op/file_operations slots using hardcoded offsets when handler symbols are unavailable. Missing required symbols now return -ENOENT. Check policy-hook registration results, mark installations complete only on success, avoid registering the policy-load hook twice, and propagate initialization/snapshot errors. Zero the status page before mapping it and validate the page-protection value with the existing helper.

Bound print_bootlog() to its 1,024-byte stack buffer by flushing long lines in chunks, including a final unterminated line.

Tradeoff: disabling hiding retains a fixed set of trampolines and the status page until reboot, with forwarding overhead; kernels lacking the required symbols cannot enable this feature.

Related manager changes and local kernel artifact support: LyraVoid/FolkPatch#220.

Validation:

• python3 tests/test_stability.py passes with AddressSanitizer and UndefinedBehaviorSanitizer: missing symbols, partial install/retry, resident disable/re-enable, busy control, policy-load retry, and 8,192-byte panic logs.
• The three modified C files compiled to ARM64 objects with NDK r26b Clang and the project's Android compile flags. Existing header warnings remain.
• git diff --check passes.
• The host regressions use stubs for kernel operations. Full kpimg linking and device validation have not been performed; these fixes do not establish the cause of any particular device's random reboot.