Add MTP decoding support for GLM-4.x MoE (#1270)

* wip: port MTP architecture

Ports the Multi-Token Prediction (MTP) architecture to the older `llama.cpp` codebase used by `ikllama`.

Changes include:
- Updating `llama_batch` to support `mtp_params`.
- Modifying `llama_decode_internal` (and `encode`) to handle MTP operations (Warmup, Update, Draft).
- Adding public APIs for MTP state management (`llama_set_draft_input_hidden_state`).
- Adapting the embedding extraction logic to skip MTP update passes.

* Refactors `server_slot` to support generic speculative decoding (MTP or Draft Model).

* core: enable hybrid outputs (logits + embeddings) for MTP support

* fix(mtp): correct KV-cache slot finding for updates

* fix(mtp): persist hidden states to prevent context corruption during drafting

* refactor(mtp): clean unused code

* fix(mtp): update server to new functions name

* fix(mtp): fix graph and save hidden state

* mtp: refactor integration, context params and kv cache search

* mtp: fix hidden state extraction and speculative acceptance flow

* server: fix MTP warmup for long prompts and reset token buffer

* llama: refactor MTP operation state to context parameters

* server: fix n_past calculation in MTP acceptance

* llama: fix mtp enable flags

* speculative: refactor MTP to use common_speculative interface

* context: remove unused signatures

* clip: fix deprecated enum-enum conversion warning

* common: fix format string crash in help message

* context: fix mtp activation logic

examples/mtmd/clip.cpp

@@ -35,7 +35,7 @@
 #include <array>
 #include <functional>
 
-#define DEFAULT_INTERPOLATION_MODE (GGML_SCALE_MODE_BILINEAR | GGML_SCALE_FLAG_ALIGN_CORNERS)
+#define DEFAULT_INTERPOLATION_MODE ((int)GGML_SCALE_MODE_BILINEAR | (int)GGML_SCALE_FLAG_ALIGN_CORNERS)
 
 // TODO: allow to pass callback from user code
 struct clip_logger_state g_logger_state = {GGML_LOG_LEVEL_CONT, clip_log_callback_default, NULL};