docs: add bible-local with architecture and decisions, fix PLAN.md versions

- bible-local/architecture/system-overview.md: scope, tech stack, key paths
- bible-local/architecture/runtime-flows.md: boot sequence, ISO build, collector flow
- bible-local/decisions/2026-03-05-nvidia-proprietary-driver.md
- PLAN.md: update KERNEL_VERSION 6.6→6.12, NVIDIA 550.54.15→590.48.01

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

bible-local/architecture/runtime-flows.md

@@ -0,0 +1,78 @@
+# Runtime Flows — bee
+
+## Boot sequence (debug ISO)
+
+OpenRC default runlevel, service start order:
+
+```
+localmount
+  └── bee-sshsetup   (creates bee user, sets password fallback)
+        └── dropbear  (SSH on port 22 — starts regardless of network)
+  └── bee-network    (udhcpc -b on all physical interfaces, non-blocking)
+        └── bee-nvidia  (depmod -a, modprobe nvidia nvidia-modeset nvidia-uvm)
+              └── bee-audit-debug  (runs audit binary, logs to /var/log/bee-audit.json)
+```
+
+**Critical invariants:**
+- Dropbear MUST start without network. Custom init in overlay has `need localmount` only — NOT `need net`.
+- bee-network uses `udhcpc -b` (background daemon) so it retries indefinitely when cable connected later.
+- bee-audit-debug uses `eend 0` always — never fails boot even if audit errors.
+
+## ISO build sequence
+
+```
+build-debug.sh
+  1. compile audit binary (skip if .go files older than binary)
+  2. build-nvidia-module.sh:
+       a. download NVIDIA .run installer (sha256 verified, cached)
+       b. extract installer
+       c. build kernel modules against linux-lts-dev headers
+       d. extract nvidia-smi + libnvidia-ml from installer
+       e. cache in dist/nvidia-<version>-<kver>/
+  3. inject authorized_keys into overlay
+  4. inject audit binary → overlay/usr/local/bin/audit
+  5. inject NVIDIA .ko → overlay/lib/modules/<kver>/extra/nvidia/
+  6. inject nvidia-smi → overlay/usr/local/bin/nvidia-smi
+  7. copy mkimg profile + genapkovl to ~/.mkimage/ AND /var/tmp/
+  8. mkimage.sh (from /var/tmp, TMPDIR=/var/tmp):
+       kernel_* section  — cached (linux-lts modloop, lz4 compressed)
+       apks_* section    — cached (downloaded packages)
+       syslinux_* / grub_* — cached
+       apkovl            — always regenerated (genapkovl-bee_debug.sh)
+       final ISO         — always assembled
+```
+
+**Critical invariants:**
+- `genapkovl-bee_debug.sh` must be in `/var/tmp/` (CWD when mkimage runs), not only `~/.mkimage/`.
+- `TMPDIR=/var/tmp` required — tmpfs /tmp is only ~1GB, too small for kernel firmware.
+- Workdir cleanup preserves `apks_*`, `kernel_*`, `syslinux_*`, `grub_*` — only clears apkovl and final image.
+- `run-builder.sh` runs build in `screen` session to survive SSH disconnects during long NVIDIA downloads.
+
+## apkovl mechanism
+
+The apkovl is a `.tar.gz` injected into the ISO at `/boot/`. Alpine's initramfs extracts it at boot, overlaying `/etc`, `/usr`, `/root` on the tmpfs root.
+
+`genapkovl-bee_debug.sh` generates the tarball containing:
+- `/etc/apk/world` — package list (apk installs these on first boot)
+- `/etc/runlevels/*/` — OpenRC service symlinks
+- `/etc/conf.d/dropbear` — DROPBEAR_OPTS="-R -B"
+- `/etc/network/interfaces` — lo only (bee-network handles DHCP)
+- `/etc/hostname`
+- Everything from `iso/overlay-debug/` (init scripts, binaries, ssh keys)
+
+## Collector flow
+
+```
+audit binary start
+  1. board collector   (dmidecode -t 0,1,2)
+  2. cpu collector     (dmidecode -t 4)
+  3. memory collector  (dmidecode -t 17)
+  4. storage collector (lsblk -J, smartctl -j, nvme id-ctrl, nvme smart-log)
+  5. pcie collector    (lspci -vmm -D, /sys/bus/pci/devices/)
+  6. psu collector     (ipmitool fru — silent if no /dev/ipmi0)
+  7. nvidia enrichment (nvidia-smi — skipped if driver not loaded)
+  8. output JSON to stdout / file / usb
+  9. QR summary to stdout (qrencode if available)
+```
+
+Every collector returns `nil, nil` on tool-not-found. Errors are logged, never fatal.