Fix LingBot KV metadata handling and unify KV config construction

[forLG]

Summary

This PR fixes TeleFuser LingBot exact-prefix reuse against the current KV runtime metadata layout and simplifies KV config construction.

Changes:

• Treat global_end_index and local_end_index as scalar metadata instead of array-like values in telefuser_lingbot.py.
• Preserve full-KV behavior when local_attn_size == -1, which is required by the default LingBot checkpoint.
• Replace the separate make_full_kv_config() and make_rolling_config() helpers with a unified make_world_kv_config() helper.
• Update the LingBot exact-prefix reuse E2E example to use the unified config helper.
• Update tests/test_world_kv_telefuser_binding.py to cover the unified make_world_kv_config() path instead of the removed rolling-config helper.

Motivation

TeleFuser provides LingBot KV metadata such as global_end_index and local_end_index as integers. The previous binding indexed them as array-like values, which breaks compatibility with the current runtime.

The example also initialized a rolling-window KV config even when the runtime uses full KV. This could make cache materialization inconsistent with the pipeline configuration.

Testing

1. Run pytest -m smoke and get all passed.

2. Run examples/exact_prefix_reuse/e2e_telefuser_lingbot.py:

   source ~/TeleFuser/.venv/bin/activate
   export ASSETS=~/lingbot-world/examples/00
   export LINGBOT_WORLD_CHECKPOINT_DIR=/public/model_zoo/lingbot-world-base-cam
   python examples/exact_prefix_reuse/e2e_telefuser_lingbot.py 
       --frame-num 42
       --prefix-chunks 2
       --image-path "$ASSETS/image.jpg"
       --action-path "$ASSETS/"
       --out-dir /tmp/worldkv_e2e

   The result is following, all checks passed:

   {
     "checks": {
       "A_cold": true,
       "B_full_hit": true,
       "B_frames_equal_A": true,
       "C_prefix_hit": true,
       "D_cold": true,
       "C_frames_equal_D": true
     },
     "all_pass": true,
     "wall_s": {
       "A": 18.212,
       "B": 5.633,
       "C": 8.193,
       "D": 15.241
     },
     "flush_s": {
       "A": 0.0,
       "B": 0.0,
       "C": 0.0,
       "D": 0.0
     },
     "fast_forward_k": {
       "A": 0,
       "B": 3,
       "C": 2,
       "D": 0
     }