fix: macOS symlink compatibility + rename config to ~/.llm_config.sh

[JewelRoam]

仓库里接口是 OpenAI 格式，并非Anthropic Messages API，叫 .anthropic.sh 有误导；另外加了个 realpath 修复。

Summary

• fix(make_tensor): Normalize both sides of os.path.relpath in symlink mode to fix macOS /var → /private/var path resolution
• rename: ~/.anthropic.sh → ~/.llm_config.sh across all files

Problem

Symlink bug on macOS

make_tensor(..., symlink=True) computes relative symlink paths with mismatched resolution:

# Before: source is resolved, destination is NOT
rel_src = os.path.relpath(
    str(path.resolve()),        # → /private/var/...
    os.path.dirname(file_path), # → /var/...  ← mismatch!
)

On macOS, /var is a symlink to /private/var. The prefix mismatch causes os.path.relpath to produce incorrect relative paths, resulting in FileNotFoundError: /private/private/var/... when downstream code calls os.path.realpath() to follow the symlink chain.

Config file naming

The LLM config variables (LLM_API_KEY, LLM_BASE_URL, LLM_MODEL) are provider-agnostic and use OpenAI-compatible API format. Naming the config file ~/.anthropic.sh is misleading. Renamed to ~/.llm_config.sh to accurately reflect its purpose.

Fix

# After: both sides consistently resolved
rel_src = os.path.relpath(
    os.path.realpath(str(opt_file_content_or_path)),
    os.path.realpath(os.path.dirname(file_path)),
)

Test

• All make_tensor self-tests pass (including symlink mode)
• All slice_view self-tests pass (depends on make_tensor symlink mode)
• Verified on macOS 15 (Darwin 25.4.0) — _copy_back_to_storage_view in st_moe_forward now resolves paths correctly