feat: Antigravity 端点签名迁移至 gemini:chat，流式 usage 提取重构与请求详情自动刷新

- Antigravity 端点签名从 gemini:cli 统一为 gemini:chat，保留向后兼容，含 DB 迁移
- 流式处理中 usage/completion/text 提取抽离为 _update_ctx_from_provider_event，
  支持 envelope 解包后提取，避免格式转换流程中重复计数
- 新增 has_format_conversion 属性，区分真正的格式转换与 envelope rewrite，
  修正 usage 展示层的格式转换标记
- 请求详情抽屉对未完成请求支持自动轮询刷新，关闭时自动停止
- 按次计费样式调整；实际成本仅在倍率非 1.0 时显示；缓存日志降级为 trace

alembic/versions/20260206_2345_e1b2c3d4f5a6_antigravity_api_format_to_gemini_chat.py

@@ -0,0 +1,116 @@
+"""Update Antigravity endpoint signature to gemini:chat
+
+Revision ID: e1b2c3d4f5a6
+Revises: b5c6d7e8f9a0
+Create Date: 2026-02-06 23:45:00.000000
+
+"""
+
+from __future__ import annotations
+
+from collections.abc import Sequence
+
+from sqlalchemy import text
+
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision: str = "e1b2c3d4f5a6"
+down_revision: str | None = "b5c6d7e8f9a0"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    conn = op.get_bind()
+
+    # --- provider_endpoints ---
+    # Update only when there is no conflicting gemini:chat endpoint for the same provider
+    # (provider_endpoints has a unique constraint on (provider_id, api_format)).
+    conn.execute(text("""
+            UPDATE provider_endpoints pe
+            SET
+                api_format = 'gemini:chat',
+                api_family = 'gemini',
+                endpoint_kind = 'chat'
+            WHERE pe.api_format = 'gemini:cli'
+              AND pe.provider_id IN (
+                SELECT id FROM providers WHERE lower(provider_type) = 'antigravity'
+              )
+              AND NOT EXISTS (
+                SELECT 1 FROM provider_endpoints pe2
+                WHERE pe2.provider_id = pe.provider_id
+                  AND pe2.api_format = 'gemini:chat'
+              )
+            """))
+
+    # Best-effort normalization for already-existing Antigravity gemini:chat endpoints.
+    conn.execute(text("""
+            UPDATE provider_endpoints pe
+            SET
+                api_family = 'gemini',
+                endpoint_kind = 'chat'
+            WHERE pe.api_format = 'gemini:chat'
+              AND pe.provider_id IN (
+                SELECT id FROM providers WHERE lower(provider_type) = 'antigravity'
+              )
+            """))
+
+    # --- provider_api_keys.api_formats (JSON array) ---
+    # Replace "gemini:cli" with "gemini:chat" in the JSON array for Antigravity keys.
+    # Uses text-level replace on the serialized JSON — safe because the value is a
+    # simple string with no special characters that could cause ambiguous replacements.
+    conn.execute(text("""
+            UPDATE provider_api_keys pak
+            SET api_formats = replace(pak.api_formats::text, '"gemini:cli"', '"gemini:chat"')::json
+            WHERE pak.provider_id IN (
+                SELECT id FROM providers WHERE lower(provider_type) = 'antigravity'
+            )
+              AND pak.api_formats IS NOT NULL
+              AND pak.api_formats::text LIKE '%"gemini:cli"%'
+            """))
+
+
+def downgrade() -> None:
+    conn = op.get_bind()
+
+    # --- provider_endpoints ---
+    conn.execute(text("""
+            UPDATE provider_endpoints pe
+            SET
+                api_format = 'gemini:cli',
+                api_family = 'gemini',
+                endpoint_kind = 'cli'
+            WHERE pe.api_format = 'gemini:chat'
+              AND pe.provider_id IN (
+                SELECT id FROM providers WHERE lower(provider_type) = 'antigravity'
+              )
+              AND NOT EXISTS (
+                SELECT 1 FROM provider_endpoints pe2
+                WHERE pe2.provider_id = pe.provider_id
+                  AND pe2.api_format = 'gemini:cli'
+              )
+            """))
+
+    # Best-effort normalization for already-existing Antigravity gemini:cli endpoints.
+    conn.execute(text("""
+            UPDATE provider_endpoints pe
+            SET
+                api_family = 'gemini',
+                endpoint_kind = 'cli'
+            WHERE pe.api_format = 'gemini:cli'
+              AND pe.provider_id IN (
+                SELECT id FROM providers WHERE lower(provider_type) = 'antigravity'
+              )
+            """))
+
+    # --- provider_api_keys.api_formats (JSON array) ---
+    conn.execute(text("""
+            UPDATE provider_api_keys pak
+            SET api_formats = replace(pak.api_formats::text, '"gemini:chat"', '"gemini:cli"')::json
+            WHERE pak.provider_id IN (
+                SELECT id FROM providers WHERE lower(provider_type) = 'antigravity'
+            )
+              AND pak.api_formats IS NOT NULL
+              AND pak.api_formats::text LIKE '%"gemini:chat"%'
+            """))