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/arch/amd64/i8042.c

@@ -24,7 +24,7 @@
 /**
  * i8042.c - PS/2 keyboard controller driver (amd64)
  *
- * Item 4.3.5 (FABRIC.md §27.5).
+ * Item 4.3.5 (FABRIC-0.md §27.5).
  */
 
 #ifndef __STARKERNEL__

src/starkernel/arch/amd64/ioapic.c

@@ -24,7 +24,7 @@
 /**
  * ioapic.c - I/O APIC driver (amd64)
  *
- * Item 4.3.5 (FABRIC.md §27.5). MADT parsing mirrors pci.c's RSDP -> XSDT ->
+ * Item 4.3.5 (FABRIC-0.md §27.5). MADT parsing mirrors pci.c's RSDP -> XSDT ->
  * table-by-signature walk (the two files don't share a header for this —
  * same duplication pci.c already has relative to a hypothetical shared
  * acpi.c, not introduced fresh here).

src/starkernel/arch/amd64/timer.c

@@ -134,7 +134,7 @@ static uint64_t vm_ns_base  = 0;
  * @p b are both large (e.g., nanosecond conversion of multi-GHz tick counts).
  * No libgcc dependency — pure inline assembly.
  *
- * FABRIC.md item 4.5d, 2026-08-11: this asm previously declared @c RDX as a
+ * FABRIC-0.md item 4.5d, 2026-08-11: this asm previously declared @c RDX as a
  * plain output (@c "=d"(hi)), which tells GCC only "I want to read RDX's
  * value after this block" — nothing told it that @c mulq writes RDX *before*
  * @c divq needs to read a *different* value (the divisor @c c) out of it.
@@ -604,7 +604,7 @@ static uint64_t calibrate_tsc_with_pmtimer(void)
             uint64_t elapsed_ns = muldiv64(elapsed_ticks, 1000000000ull, PMTIMER_FREQ_HZ);
             if (elapsed_ns == 0) return 0;
 
-            /* FABRIC.md item 4.5d, 2026-08-11: this file's own comments already
+            /* FABRIC-0.md item 4.5d, 2026-08-11: this file's own comments already
              * flag TSC non-monotonicity as a real risk under TCG ("invariant
              * TSC not present under hypervisor... no determinism guarantees").
              * If end_tsc < start_tsc, this subtraction wraps to a huge unsigned
@@ -1378,7 +1378,7 @@ const timer_calibration_record_t *timer_calibration_record(void)
 /**
  * @brief Read the raw counter the amd64 heartbeat is paced against.
  *
- * Item 0.8 (FABRIC.md §25.1): the shared heartbeat.c owns
+ * Item 0.8 (FABRIC-0.md §25.1): the shared heartbeat.c owns
  * heartbeat_init()/heartbeat_tick()/heartbeat_service()/heartbeat_ticks()/
  * heartbeat_trust()/heartbeat_state() and the variance/trust math that used
  * to live in this file. This is the one piece that stays per-architecture