feat(core): model-architecture seam, chat templates, text antiprompt

[khalilswdp]

Summary

The engine is hardcoded to GLM-5.2: chat template, eos token, and forward-pass dispatch are all baked into colibri.c, so a second model family currently means a second binary (like olmoe.c). The smallest change that fixes this is a load-time seam:

• arch.h + arch_glm.c — a ModelArch descriptor registry selected from config.json "architectures"[0] (falling back to "model_type"). Unknown architectures are refused up front with the supported list, instead of silently mis-reading another model's weights. A config with neither field predates the registry and keeps loading as GLM with a notice, so existing snapshots and oracle fixtures are unaffected.

• engine.h — the shared engine types (Cfg, QT, Layer, Model, …) move verbatim out of colibri.c so a future arch module can compile as a standalone .c. The forward pass dispatches attention_rows/moe through a two-pointer vtable bound at load; GLM binds the existing built-ins. No speculative fields — a new family adds its fields in the PR that consumes them.

• Chat template/eos from the descriptor — serve/run build turns from chat_prefix/chat_turn/chat_think/chat_eos instead of hardcoded GLM strings; the GLM descriptor is byte-identical to the previous literals. router_bias gains NULL guards for families without e_score_correction_bias.

• antiprompt.h — a quantized model can emit a role delimiter like <|user|> as ordinary text tokens, so the id stop never fires (and serve drops role-marker ids from the stop set, [Bug]: Tool Calling Fail in serve API #401) and the model hallucinates the next turn. This matches the decoded text, streamed with a (longest-needle − 1) hold-back so delimiters split across tokens are caught and never printed. COLI_ANTIPROMPT overrides or disables it.

Also: COLI_TPS_EVERY makes the tok/s heartbeat cadence configurable (default 8; the hardcoded 16 meant short replies never produced a reading; 0 silences).

Validation

• make -C c check — clean build, 0 new warnings, C unit tests + Python
  stdlib tests pass (the two -Wformat-truncation notes gcc 15 emits are
  pre-existing on dev; a separate small PR fixes them)
• CUDA changes — n/a (no kernel changes; arch_glm.o is pure C linked into
  every build)
• No performance claims in this PR

Compatibility

• The default CPU build remains dependency-free — the registry is pure C,
  two new headers + one .c, no new deps
• No model files, generated binaries, or benchmark artifacts included
• Defaults changed: none. All new behavior is selected by the model's own
  config.json or opt-in env vars (COLI_ANTIPROMPT, COLI_TPS_EVERY).
• .gitignore gains pattern rules for build outputs (*.o, *.obj, …) so new
  sources' objects don't leak into git status.

[JustVugg]

Thanks for this — the architecture seam is a nice direction. It now conflicts on dev (colibri.c / Makefile moved with recent merges). Could you rebase onto latest dev? CI is green; once it's clean we can land it, then #670 on top of it.

[khalilswdp]

Rebased onto latest dev (a3a5a75) — applied cleanly, no conflicts. The conflicts you saw were from an accidental fork-sync merge that briefly polluted the branch; it's been removed and the branch is back to the single seam commit, now based on current dev. Ready to land — and the windows suite is already re-stacked on top for the follow-up.

[khalilswdp]

Rebased onto latest dev (c67dbab). One real conflict with #679: both changes guard the spec-decode emit loop — your g_mux_stop/g_mux_cancel (client STOP/CANCEL mid-turn) and this PR's g_astop (text antiprompt) — resolved as the union of the stop conditions so both features coexist.

Why the antiprompt guard exists at all: a heavily-quantized GLM can emit a role delimiter like <|user|> as ordinary text tokens (<,|,user,|,>) instead of the atomic control-token id — the id stop never fires and the model runs on, hallucinating the next turn. And in serve mode the role-marker ids are deliberately dropped from the stop set anyway (#401, protecting <tool_call> blocks from int4 argmax noise), so even the atomic token wouldn't stop there. The antiprompt matches the decoded text instead, streaming with a short hold-back (longest needle − 1) so a delimiter split across tokens is caught and never leaked to the client.

Full local gate green at the rebased tip: build + C/Python suites, token-exact oracle 32/32 TF / 20/20 greedy, no new warnings. Ready to land — the windows suite is re-stacked on top and ready to follow.

[JustVugg]

dev has moved a fair amount (v1.3.0: Kimi K3 and Inkling engines, the ragged-attention grouped-scale fix, CUDA_RELEASE_HOST default, the Inkling expert-cache fix). This PR now conflicts — could you rebase onto latest dev? Nothing is wrong with the change itself; CI was green where it ran. Ping me once it's clean and I'll review/merge.