feat: add PostingStrategy ABC and PostResult dataclass

app/services/platforms/base.py

@@ -0,0 +1,37 @@
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from dataclasses import dataclass, field
+
+
+@dataclass
+class PostResult:
+    url: str
+    metadata: dict | None = field(default=None)
+
+
+class PostingStrategy(ABC):
+    """Base class for all posting output types.
+
+    Subclasses must set class attribute `campaign_type` matching the value
+    stored in campaigns.type.
+    """
+
+    campaign_type: str  # e.g. "reddit_post", "reddit_comment", "blog_post"
+
+    @abstractmethod
+    def execute(
+        self,
+        *,
+        target: str,
+        title: str,
+        body: str,
+        flair: str | None = None,
+        extra: dict | None = None,
+    ) -> PostResult:
+        """Execute the post. Raise on failure. Return PostResult on success."""
+        ...
+
+    def supports_dupe_guard(self) -> bool:
+        """Return False to skip the weekly-dupe-guard check for this type."""
+        return True

tests/services/platforms/test_base.py

@@ -0,0 +1,12 @@
+from app.services.platforms.base import PostResult
+
+
+def test_post_result_requires_url():
+    r = PostResult(url="https://reddit.com/r/test/comments/abc")
+    assert r.url == "https://reddit.com/r/test/comments/abc"
+    assert r.metadata is None
+
+
+def test_post_result_accepts_metadata():
+    r = PostResult(url="https://example.com", metadata={"id": "abc123"})
+    assert r.metadata == {"id": "abc123"}