Initial commit: Screen Leads app

Screen-capture lead tool: capture agent, Claude vision extractor with
pluggable site recipes (LinkedIn), canonical funnel model, SQLite storage,
FastAPI backend, dashboard, and setup/run scripts.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

ai/recipes/base.py

@@ -0,0 +1,36 @@
+"""SiteRecipe interface. Each supported site implements one of these; adding a
+new site is a drop-in module registered in ai/recipes/__init__.py — the core
+capture loop never changes.
+"""
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from typing import Any, Optional
+
+from core.models import Lead, PageContext, PageMatch
+
+
+class SiteRecipe(ABC):
+    site_id: str = ""
+    display_name: str = ""
+    enabled: bool = True
+    # Which extracted page_type is a capturable target (e.g. a person's profile).
+    target_page_type: str = "profile"
+
+    @abstractmethod
+    def matches(self, ctx: PageContext) -> Optional[PageMatch]:
+        """Return a PageMatch if this recipe recognises the page, else None."""
+
+    @property
+    @abstractmethod
+    def extraction_schema(self) -> dict[str, Any]:
+        """JSON schema (structured-output format) for the raw extraction."""
+
+    @property
+    @abstractmethod
+    def extraction_prompt(self) -> str:
+        """Instruction given to the vision model alongside the screenshots."""
+
+    @abstractmethod
+    def to_canonical(self, raw: dict[str, Any]) -> Lead:
+        """Map this site's raw extraction to the canonical Lead schema."""