live-image: real /init + verbose boot for first-boot diagnosis

Host boots past kernel init and then stalls silently. ACPI DSDT error
about TXHC.RHUB.SS01 is benign noise (Tiger Lake firmware bug) — the
actual problem is that nothing between kernel handoff and (maybe)
systemd is visible on the console.

Two changes:

1. Replace the /init → sbin/init symlink with a real shell script
   (live-image/mkosi.extra/init) that mounts /proc /sys /dev /dev/pts
   /dev/shm /run before execing systemd. Systemd has fallback mount
   code for these, but when it fails the failure is silent. Doing it
   explicitly in /init keeps failures visible and avoids the fragile
   symlink-resolution trick.

2. Drop 'quiet' from the kernel cmdline and add loglevel=7 plus
   systemd.log_target=kmsg + journald.forward_to_console=1 so every
   early-boot message reaches both tty0 and ttyS0. Will be dialed
   back once boot is stable.

Also: .gitattributes pins LF on live-image/, .gitea/, Makefile, and
*.sh so Windows checkouts don't break shell scripts and Makefile
recipes with CRLF. /init also gets chmod 0755 in repack-initrd as a
belt-and-braces against mode loss on non-Linux checkouts.

internal/pxe/ipxe.go

@@ -35,13 +35,20 @@ func BuildScript(p IPXEParams) string {
 	if p.TLSCertFPR != "" {
 		cmdline = append(cmdline, fmt.Sprintf("vetting.cert_fpr=%s", p.TLSCertFPR))
 	}
-	// Reduce kernel log noise during the test run; keep loglevel high enough
-	// for boot failures to still show up on the console.
+	// Verbose kernel + systemd logging on both the video console and the
+	// serial port so first-boot failures on unfamiliar hardware aren't
+	// invisible. Drop `quiet` entirely — once boot is stable we can
+	// re-add it. systemd.log_target=kmsg makes early systemd go through
+	// the same dmesg buffer as the kernel, so nothing is lost before
+	// journald comes up.
 	cmdline = append(cmdline,
 		"console=tty0",
 		"console=ttyS0,115200n8",
 		"ip=dhcp",
-		"quiet",
+		"loglevel=7",
+		"systemd.log_level=info",
+		"systemd.log_target=kmsg",
+		"systemd.journald.forward_to_console=1",
 	)
 
 	var b strings.Builder