Additional kernels & improved color reuse & multi-hop routing

[luxfg]

Summary

Compiler and sample work to pack more communication onto fewer colors, recycle task IDs across epochs, and run new kernels on WSE-2 and WSE-3.

Routing and color reuse

• Bundle overlapping 1D interval shifts onto one color: nearest-destination-first send order, local switch-advance at each source, and counter filters at destinations (detect_shift_bundles; documented in irspec/docs/spatial/routing_wse.md).
• Collapse and emit switch configurations (FilterConfig, standalone routes) instead of a per-hop switch-advance wavelet. WSE-2 local flips use .advance_switch on the last data wavelet; WSE-3 emits SWITCH_ADV.
• Assign fabric input/output queues by occupancy span so a color keeps its queue across a gap. Two colors share a queue only when their spans do not overlap (WSE-2). WSE-3 binds a queue to its color for the whole kernel and does not remap.
• On WSE-3, assign microthreads (.ut_id) independently of queues so an input and an output of the same number can run together.
• Reject statically overlapping compute and dataflow rectangles in one phase at compile time.

Task IDs

• Recycle local-task IDs when tasks are ordered, and bind data tasks that share a color to one hardware slot with a rebind between epochs.
• WSE-3: @get_data_task_id takes the fabin input queue, not a color. Program queues are 2–7 (memcpy owns 0 and 1). Local-task allocation skips memcpy-reserved IDs, including WSE-3’s color-21 LOCAL_MEMCPYD2H_DATA hole.
• Runtime memcpy path supports 16-bit payloads.

Samples

• Sparse matrix–vector (samples/spatial/blas/spmv.sptl).
• Batcher odd-even sort, static, bundled, and WSE-3 origin-pooled, generalized to K keys per PE and R independent rows (samples/spatial/sort/).
• Looped odd-even transposition sort on four static neighbour channels (odd_even_sort_1D_looped.sptl).
• 2D shearsort on eight static neighbour channels (shearsort_2D_looped.sptl, WSE-3; four inbound colours in one epoch).
• Shift and exchange bundle microkernels (samples/spatial/simple/).