feat(kernel): Artemis grows to fill the stick at its first boot -- metadata only, capped at 256 GiB (#92, Task 2)

Task 2 of plan 2026-10-29-stick-5, accepted in full:
- amd64, aarch64, riscv64: PARITY:V4_POST tests=538 pass=538 fail=0,
  POST: PASSED, [zuse@Hera] ok>; dict_hash 0xfec8c47cfc6f437f on the three
- the PC stick loaded high: 538/538, POST: PASSED, the prompt
- make -C v4 test-32: 39 programs, 0 failures

The acceptance boots' logs, the accept-*.txt verdicts and test-32's output
(logs/20261108-123847/verdicts/). The plan's Task 2 steps ticked; FABRIC-3
XLVIII.9, with one item for a ruling: blk_flush rewrites the whole BAM, now
sized for 256 GiB.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GE3SDvQn5EoxdGufk84zz2

docs/v4.0.0/plans/2026-10-29-stick-5-proxy-zuse-and-real-zuse.md

@@ -195,7 +195,7 @@ xHCI USB sticks, `scripts/qemu_session.py`.
   GPT, open Artemis, `sk_v4_grow_artemis`, then on as Task 1. Under 8 GB → the "not grown" line,
   once. Past the cap → the "left unused" line.
 
-- [ ] **Step 1: Failing tests:**
+- [x] **Step 1: Failing tests:**
   - **`stick_grow`** (amd64, `--target qemu-stick --stick-gib 16`): first boot: `grown to fill the
     stick`, Artemis's `blk: disk` line over 12000000 user blocks (`KERNEL_ARGS=--log-level=info`),
     the genesis line, the prompt; the first boot's time printed by the harness (POST to prompt).
@@ -205,11 +205,11 @@ xHCI USB sticks, `scripts/qemu_session.py`.
     prompt. Today: FAIL (no line).
   - **`check_images.sh`:** the PC stick's and data stick's Artemis BAM is the cap's size
     (`mkartemis --check` reports it). Today: FAIL.
-- [ ] **Step 2:** Run each: FAIL as listed.
-- [ ] **Step 3:** Implement.
-- [ ] **Step 4:** They pass; regression: `genesis`, `stick_genesis`, `stick_zuse`, `two_sticks`,
+- [x] **Step 2:** Run each: FAIL as listed.
+- [x] **Step 3:** Implement.
+- [x] **Step 4:** They pass; regression: `genesis`, `stick_genesis`, `stick_zuse`, `two_sticks`,
   `artemis_unsigned`, `midpull` (replug: not grown again).
-- [ ] **Step 5:** Suite; full acceptance; commit `feat(kernel): Artemis grows to fill the stick at
+- [x] **Step 5:** Suite; full acceptance; commit `feat(kernel): Artemis grows to fill the stick at
   its first boot -- metadata only, capped at 256 GiB` with the logs and the first-boot time.
 
 ### Task 3: acceptance on a fresh data stick