Clean up daemon and compiler mounts during KernelSU soft reboot

[bartasc4]

KernelSU replays module startup while Vector's detached daemon can survive. Starting another daemon can collide with the survivor and inherit its compiler bind mounts, causing a wrapper to be cached as the stock dex2oat.

This change prepares the next startup in the module scripts:

• Identify the old daemon by module cwd, executable and private resource-cache mount; stop it and wait for exit without depending on its process name.
• Detach only visible compiler mounts rooted in this module, including replaced wrapper inodes and stacked mounts. Preserve other modules' mounts.
• Clean up in emulated-soft-reboot.sh, in post-fs-data.sh for the first update from a version without that hook, and before service.sh starts a replacement. Install both new stage scripts.

The production diff is limited to four shell files. It adds no application hooks, persistent PID markers or SELinux mode changes; non-KernelSU startup and existing daemon arguments are preserved.

Related to #878. This builds on H3XDaemon's lifecycle hook in #914 and ManiaciaChao's stale-mount diagnosis. It is a standalone implementation against master that overlaps #914, not a patch to apply on top of it. #1008 provides a separate compiler recursion guard and remains useful for failures outside this managed restart path.

Validation evidence: Sanitized diagnostic archive (ZIP). Includes selected device log excerpts, host test results, installer checks and the source patch.

Validation and limits

• 24 Linux integration tests pass under dash, BusyBox ash/applets and mksh, using real isolated processes and bind mounts. Includes repeated replacements, first-update ordering, unrelated-process/mount preservation, and refusing startup on cleanup failure.
• The real installer installs and verifies both hooks for ARM, ARM64, x86 and x86_64 host fixtures. These fixtures do not establish Android ABI compatibility.
• Earlier device observation: Android 12/API 31, ARM64, KernelSU Next 3.4.2 and NeoZygisk; one completed emulated cycle, one replacement Vector daemon, stock compiler FDs distinct from wrappers, single compiler bind mounts, IPC reconnection and module loading. The four production scripts are byte-identical to that tested local build.
• That device build included other local changes and an unrelated environment workaround. This is not a controlled stock-versus-patched comparison. The current upstream-based PR has not been installed on the phone or rebuilt end to end; no all-version or repeated-device-cycle claim is made.
• A foreign mount covering a Vector mount is deliberately left intact. This does not resolve injection-provider lifecycle bugs or every possible soft-reboot failure.

Reproduce: python3 tests/soft-reboot/run_tests.py (Linux; requirements in tests/soft-reboot/README.md).