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/starkernel/capsule/capsule_mint.c

@@ -30,7 +30,7 @@
 #define MINT_IDENTITY_SRC_DEVBLOCKS 2u /* 1 seed record + 1 personality source */
 #define MINT_METADATA_DEVBLOCKS   5u  /* devblocks 0..4 reserved */
 
-/* Real, working, minimal default personality -- FABRIC-3.md §F.6/§F.8's
+/* Real, working, minimal default personality -- FABRIC-2.md §F.6/§F.8's
  * "default personality content" question stays open (mint-time-fixed vs.
  * user-editable), but the identity this mints must actually do something
  * when RUNCAP births it, not just exist. Needs the "Block NNNN" header
@@ -43,7 +43,7 @@
  * A minted identity's RUNCAP-born VM is not exempt from that pump, so
  * omitting this left it spamming "UNKNOWN WORD: 'MSG-TICK'" every idle
  * tick forever from the moment WIREBIND made the VM live -- found live
- * minting a real second identity (FABRIC-3.md §F.26 follow-up). */
+ * minting a real second identity (FABRIC-2.md §F.26 follow-up). */
 static const char MINT_DEFAULT_PERSONALITY[] =
     "Block 4999\n"
     "S\" common:messaging.4th\" EXEC\n"