fix(openai): strengthen streaming tool call dedup to prevent false evictions

[majiayu000]

Summary

The deduplication heuristic added in v0.32 (streaming.rs ~line 211) evicts a tool call entry when a new SSE chunk arrives at the same index with a different id. This breaks providers (e.g. GLM-4 via OpenAI-compatible endpoints) that send a unique id on every SSE delta chunk for the same logical tool call — each chunk triggers a false eviction, yielding incomplete fragments as "completed" tool calls.

Fix: Strengthen the eviction condition to require both id AND name to be non-empty and different from the existing entry. A genuinely new tool call at the same index (the LiteLLM/OneAPI gateway case) always carries a new non-empty name, while continuation chunks from providers like GLM-4 have an empty name.

Fixes #1508

Changes

• Added name comparison to the dedup eviction guard: eviction now requires both a new non-empty id that differs and a new non-empty name that differs
• Added regression test test_unique_id_per_chunk_single_tool_call reproducing the exact GLM-4 scenario from the issue

Test plan

• New test test_unique_id_per_chunk_single_tool_call verifies GLM-4 chunks with unique IDs accumulate into one tool call
• Existing test test_duplicate_index_different_id_tool_calls still passes (LiteLLM/OneAPI gateway case)
• All 10 streaming tests pass
• cargo fmt clean
• cargo clippy clean