Add virtual memory support: PE_MMU, VA allocator, fabric MmuMapMsg

Implement VA/MMU layer (ADR-0011 Phase 1) enabling Triton kernels to use
contiguous virtual addresses on sharded tensors.

Key changes:
- PE_MMU component: hybrid inbox (MmuMapMsg) + sync translate() for PE_DMA
- VirtualAllocator + PEMemAllocator: free-list with coalescing
- MmuMapMsg/MmuUnmapMsg fabric path with SIP-level routing
- DPPolicy-based mapping: replicate=local, sharded=broadcast
- Tensor lifecycle: del + weakref cleanup, context manager
- Rename: TensorHandle.pa→addr, DmaReadCmd.src_pa→src_addr, ctx→torch

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/kernbench/runtime_api/kernel.py

@@ -69,6 +69,7 @@ class TensorArgShard:
 class TensorArg:
     shards: tuple[TensorArgShard, ...]
     arg_kind: Literal["tensor"] = "tensor"
+    va_base: int = 0  # VA base address for the entire tensor
 
 
 @dataclass(frozen=True)
@@ -121,3 +122,33 @@ class PeDmaMsg:
     nbytes: int
     is_write: bool = False
     msg_type: Literal["pe_dma"] = "pe_dma"
+
+
+@dataclass(frozen=True)
+class MmuMapMsg:
+    """MMU mapping install: broadcast VA→PA entries to target PEs.
+
+    Sent via fabric: Host → PCIE_EP → IO_CPU → M_CPU → NOC → PE_MMU.
+    target_sips controls which SIPs receive the message.
+    """
+
+    correlation_id: str
+    request_id: str
+    entries: tuple[dict, ...]  # ({"va": int, "pa": int, "size": int}, ...)
+    target_sips: tuple[int, ...] | Literal["all"] = "all"
+    target_cubes: tuple[int, ...] | Literal["all"] = "all"
+    target_pe: int | Literal["all"] = "all"
+    msg_type: Literal["mmu_map"] = "mmu_map"
+
+
+@dataclass(frozen=True)
+class MmuUnmapMsg:
+    """MMU mapping removal: broadcast VA ranges to unmap from all PEs."""
+
+    correlation_id: str
+    request_id: str
+    entries: tuple[dict, ...]  # ({"va": int, "size": int}, ...)
+    target_sips: tuple[int, ...] | Literal["all"] = "all"
+    target_cubes: tuple[int, ...] | Literal["all"] = "all"
+    target_pe: int | Literal["all"] = "all"
+    msg_type: Literal["mmu_unmap"] = "mmu_unmap"