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

include/starkernel/capsule_vm_physics.h

@@ -41,7 +41,7 @@
 #define STARKERNEL_CAPSULE_VM_PHYSICS_H
 
 #include <stdint.h>
-#include "starkernel/vm_uuid.h" /* VMUuid -- FABRIC.md item 3.8 */
+#include "starkernel/vm_uuid.h" /* VMUuid -- FABRIC-0.md item 3.8 */
 
 #ifdef __cplusplus
 extern "C" {
@@ -82,7 +82,7 @@ void vm_physics_retire(VMUuid vm_id);
  * (amount = elapsed_ticks * fleet_transfer_slope_q48 >> 16) and appends
  * vm_id to the fleet's rolling touch-history window.
  *
- * Restated on the virtual tick (FABRIC.md item 2.1, 2026-08-04): no
+ * Restated on the virtual tick (FABRIC-0.md item 2.1, 2026-08-04): no
  * longer takes a wall-clock timestamp. Reads fleet_heartbeat_tick_count
  * internally, which is execution-paced (advanced once per vm_tick()
  * call, see vm_physics_heartbeat_tick), so the transfer this produces is