arcint 1.2.1 — faster Flash-Next CPU misses

This is not the current release. The current one is here, with its changes in CHANGELOG.md.

Flash-Next decodes faster: the expert cache's CPU miss path gets Strata's
multi-token rows for the remaining expert types, and every miss of a verify
window goes to the CPU.

• 0063 (contrib/llama.cpp/README.md): Strata's multi-token AVX2 rows
  (src/kernels/cpu/iq_avx2.cpp) for IQ2_XS, IQ3_XXS, IQ3_S and IQ4_NL, so
  every layer of the served Flash-Next GGUFs takes the fast path (before,
  only layers whose three projections were IQ2_S, IQ2_XXS or Q2_0 did; the
  rest ran ggml-cpu's single-token dot products). GGML_OPENCL_CPU_MISS_MAX
  defaults to 64 (was 16): with 10 experts a token and at most 4 tokens a
  verify window that is every miss on the CPU, as Strata does.

Runtime: llama.cpp 3e4dfa8 with contrib/llama.cpp/patches (60
patches, 0001-0063 without 0031, 0055 and 0061); dependencies as in 1.2.0.
arcint-stt (1.2.0) and arcint-imggen (1.1.1) are unchanged.

Release check (measured-here, 2026-10-20, the B60, the pre-tag
package with the Flash-Next unit's flags): IQ3_XXS decodes 38.08 / 38.02
t/s on six answers (1.2.0: 33.85 / 33.87), prefill 622 t/s at 20k, KL as
served 0.2173 against Q8_0 (1.2.0: 0.2191), Paris and the needle right.
Measured the evening before on dev builds (Flash-Next campaign, stage 10):
each kernel equal to ggml-cpu's dot product on test data and 1.8-2.9x
faster at four tokens; the old path forced back on the patched build at the
baseline (so the gain is the new rows); UD-Q3_K_XL 12.5 -> 16.7 t/s, below
the operator's 20 t/s line for switching quants, so IQ3_XXS stays. The
other services do not use the miss path (code); their 1.2.0 checks stand.
A byte tripwire, reported: three of IQ3_XXS's eight answers change wording,
and the forced-old-path control also differs from the base build, so the
difference is not only the new rows; not explained; the answers and the KL
are right.

Packages (Debian trixie, amd64): arcint 1.2.1-1; arcint-stt stays 1.2.0-1, arcint-imggen 1.1.1-1.