boot: the /system tree is the system image — loader-built ramdisk, spawn by path

Retire the build-time ramdisk packer and the packed initial-ramdisk.img.
make-fat-image.py now lays every user binary out at its FHS path on the
boot volume (system/services, system/drivers, system/tests), and the EFI
loader walks \system at boot, packing what it finds into an in-RAM v2
initial_ramdisk whose entry names are full FHS paths. init rides the
table like every other binary: its dedicated handoff fields are gone and
the kernel spawns PID 1 via the same lookup as everyone else
(process.spawnBundled).

system_spawn resolves names by exact path first, then unique basename,
and normalizes argv[0] to the stored path — so task names (and, next,
the tagged log ring's attribution) are honest binary paths everywhere.
initrd v2 rejects the old magic so a stale image fails loudly.

Groundwork for per-process logging (/var/log/<boot-stamp>/<binary-path>.log)
and the kernel-VFS /system mount.

system/boot-handoff.zig

@@ -147,15 +147,11 @@ pub const BootInformation = extern struct {
     /// A device-tree boot path leaves this 0 and (later) fills a `device_tree_blob`
     /// field instead, so the kernel discovers devices without knowing what booted it.
     acpi_rsdp: u64 = 0,
-    /// The raw `/system/services/init` ELF image, read off the boot volume by the loader
-    /// into memory that survives the handoff (classified reserved, so the kernel
-    /// identity-maps it and never allocates over it). 0/0 = no init found — the
-    /// kernel boots without user space. Grows into a full initial_ramdisk handoff later.
-    init_base: u64 = 0,
-    init_len: u64 = 0,
-    /// The initial_ramdisk image (a bundle of extra user binaries — the VFS server and
-    /// device drivers), read off the boot volume into memory that survives the
-    /// handoff, same as `init` above. 0/0 = no initial_ramdisk. See system/initial-ramdisk.zig.
+    /// The initial_ramdisk image: every user binary from the boot volume's /system
+    /// tree (init included), packed by the loader into memory that survives the
+    /// handoff (classified reserved, so the kernel identity-maps it and never
+    /// allocates over it). Entries are named by full FHS path. 0/0 = no binaries
+    /// found — the kernel boots without user space. See system/initial-ramdisk.zig.
     initial_ramdisk_base: u64 = 0,
     initial_ramdisk_len: u64 = 0,
 };