Rename FABRIC series: FABRIC.md->0, FABRIC-2.md->1, FABRIC-3.md->2, FABRIC-4.md unchanged

FABRIC.md -> FABRIC-0.md
FABRIC-2.md -> FABRIC-1.md
FABRIC-3.md -> FABRIC-2.md (the current/living document)
FABRIC-4.md unchanged (new #3 to follow separately)

Every cross-reference repo-wide updated to match, including doc-comment
citations inside kernel source (.c/.h) files -- done via an ordered
placeholder substitution (FABRIC-3.md->placeholder2, FABRIC-2.md->
placeholder1, FABRIC.md->placeholder0, then placeholders resolved to
final names) in a single pass per file to avoid double-shifting
already-renamed references.

One line in capsules/font.4th grew past the 64-char block-format limit
as a side effect of the longer filename; shortened it and reverified
with mkcapsule --lint (34/34 pass) before rebuilding.

Verified 3-arch boot to ok> (amd64/aarch64/riscv64, each in the
foreground) after the fix; logs and DoE CSVs from this session's
verification runs included per this repo's own audit-artifact
convention.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019YcT3H2PQeyujrzjqS3Var

src/block_subsystem.c

@@ -74,7 +74,7 @@
 /* Single-block relocation (Milestone 2h+). One reserved 4 KiB devblock:
  * a 4-byte count prefix plus up to BLK_RELOC_MAX_ENTRIES 8-byte
  * {home_lbn, actual_lbn} pairs (500*8+4 = 4004 <= 4096). Relocations are
- * expected rare, not routine -- see FABRIC-2.md's own design writeup --
+ * expected rare, not routine -- see FABRIC-1.md's own design writeup --
  * so a linear-scanned fixed array is deliberate, matching this file's
  * existing tolerance for small bounded scans (DISK_CACHE_SLOTS above,
  * BLK_VM_SLOTS in block_words.c are the same shape). */
@@ -193,7 +193,7 @@ static struct {
 
 /* Redirect lbn through the relocation table if it's been moved elsewhere.
  * The single choke point every public LBN-consuming entry point below
- * calls first -- see FABRIC-2.md's design writeup for why this is an
+ * calls first -- see FABRIC-1.md's design writeup for why this is an
  * LBN->LBN redirect rather than a new storage-allocation mechanism, and
  * why it's safe for every downstream function (BAM offset math, cache
  * lookup, lbn_to_slot() itself) to stay completely unaware a substitution
@@ -706,7 +706,7 @@ int blk_subsys_attach_device(struct blkio_dev *dev) {
      * device becomes the owner. A later-attached second disk-backed
      * device (e.g. a USB drive attaching after Artemis's own disk) must
      * NOT overwrite the already-loaded table with its own (likely empty)
-     * one. See FABRIC-2.md's design writeup for why "first attached wins"
+     * one. See FABRIC-1.md's design writeup for why "first attached wins"
      * is a pragmatic default, not a general multi-primary-device answer. */
     if (slot->dev && first_disk_slot() == slot) {
         (void) reloc_load_from_disk(slot);
@@ -771,7 +771,7 @@ int blk_subsys_detach_device(struct blkio_dev *dev) {
     return BLK_OK;
 }
 
-/* Milestone 2h+ single-block relocation -- see FABRIC-2.md's design
+/* Milestone 2h+ single-block relocation -- see FABRIC-1.md's design
  * writeup for the full reasoning. Mechanical primitive only: this
  * function does not decide *whether* a relocation should happen (ACL's
  * job) or validate that target_lbn is genuinely owned by whoever is
@@ -1136,7 +1136,7 @@ int blk_set_volume_meta(const blk_volume_meta_t *meta) {
     return BLK_OK;
 }
 
-/* FABRIC-3.md §I.2, 2026-09-04: same dev-pointer slot lookup
+/* FABRIC-2.md §I.2, 2026-09-04: same dev-pointer slot lookup
  * blk_subsys_detach_device() already does internally, exposed publicly
  * for the first time so a caller can scope a scan/query to one specific
  * attached device. */
@@ -1276,7 +1276,7 @@ int blk_set_meta(uint32_t block_num, const blk_meta_t *meta) {
     return BLK_OK;
 }
 
-/* BMAPFMT field accessors -- FABRIC-3.md §H.12 step 14. Thin
+/* BMAPFMT field accessors -- FABRIC-2.md §H.12 step 14. Thin
  * read-modify-write wrappers over blk_get_meta()/blk_set_meta() above,
  * which already own caching/dirty-tracking -- these add no state of
  * their own. */
@@ -1355,7 +1355,7 @@ int blk_flags_set(uint32_t block_num, uint64_t flags) {
     return blk_set_meta(block_num, &meta);
 }
 
-/* FABRIC-3.md §F.11/§I.2, built 2026-09-04. is_lbn_zero() -- BLK_FLAG_
+/* FABRIC-2.md §F.11/§I.2, built 2026-09-04. is_lbn_zero() -- BLK_FLAG_
  * CLAIMED clear AND owner_fp all-zero is "unowned"; either alone would
  * misclassify a claimed-but-not-yet-fp-stamped or fp-stamped-but-
  * evicted devblock, neither of which should exist given owner_fp is
@@ -1459,7 +1459,7 @@ int blk_meta_relocate_devblock(uint32_t home_devblock, uint32_t target_devblock)
     return blk_set_meta(home_devblock, &home_meta);
 }
 
-/* FABRIC-3.md §I.2, 2026-09-04: heat/wear-leveling migration trigger.
+/* FABRIC-2.md §I.2, 2026-09-04: heat/wear-leveling migration trigger.
  * Uses blk_meta_t.write_count -- already present, already documented
  * for exactly this purpose ("Number of writes (wear leveling)"), no new
  * cross-subsystem query needed (Stadium's own compudynamics block heat,