Keep PR 900 overrides bounded and opt-in

The PR adds API limit overrides and static proxy support, but the review found that the default proxy provider changed to an invalid static placeholder and the new API fields accepted unbounded values. This keeps the existing proxy default intact, makes static proxy explicit via config or CLI, validates API limit ranges, and adds focused regression coverage for both paths.

Constraint: PR branch must remain contributor-branch compatible and avoid adding dependencies

Rejected: Keep static as the default provider | breaks existing --enable_ip_proxy defaults with an invalid placeholder URL

Rejected: Accept arbitrary integer limits | lets API callers request negative or excessive crawl sizes

Confidence: high

Scope-risk: narrow

Directive: Do not change proxy provider defaults when adding new providers; new providers should be opt-in and covered by provider-specific tests

Tested: uv run pytest tests/test_api_limits.py tests/test_static_proxy_provider.py

Tested: uv run pytest tests

Tested: uv run pytest test/test_utils.py

Tested: uv run python -m compileall api cmd_arg config proxy tests

Tested: git diff --cached --check

Not-tested: Live crawler run against external platforms or real proxy vendor endpoints

api/schemas/crawler.py

@@ -18,7 +18,10 @@
 
 from enum import Enum
 from typing import Optional, Literal
-from pydantic import BaseModel
+from pydantic import BaseModel, Field
+
+
+MAX_API_LIMIT_COUNT = 10000
 
 
 class PlatformEnum(str, Enum):
@@ -71,8 +74,8 @@ class CrawlerStartRequest(BaseModel):
     save_option: SaveDataOptionEnum = SaveDataOptionEnum.JSONL
     cookies: str = ""
     headless: bool = False
-    max_notes_count: Optional[int] = None
-    max_comments_count: Optional[int] = None
+    max_notes_count: Optional[int] = Field(default=None, ge=1, le=MAX_API_LIMIT_COUNT)
+    max_comments_count: Optional[int] = Field(default=None, ge=1, le=MAX_API_LIMIT_COUNT)
 
 
 class CrawlerStatusResponse(BaseModel):