Establish AAISA research foundation

src/aaisa/config.py

@@ -0,0 +1,54 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from pathlib import Path
+import tomllib
+
+from .models import Severity
+
+
+DEFAULT_EXCLUDES = (".git", ".venv", "__pycache__", "build", "dist", "node_modules")
+
+
+@dataclass(frozen=True, slots=True)
+class Config:
+    max_file_bytes: int = 2 * 1024 * 1024
+    minimum_severity: Severity = Severity.LOW
+    exclude: tuple[str, ...] = DEFAULT_EXCLUDES
+    enabled_rules: tuple[str, ...] | None = None
+
+    @classmethod
+    def from_file(cls, path: Path | None) -> "Config":
+        if path is None:
+            return cls()
+        with path.open("rb") as handle:
+            data = tomllib.load(handle)
+        scan = data.get("scan", {})
+        rules = data.get("rules", {})
+        max_bytes = int(scan.get("max_file_bytes", cls.max_file_bytes))
+        if max_bytes < 1:
+            raise ValueError("scan.max_file_bytes must be positive")
+        excluded = tuple(str(item) for item in scan.get("exclude", DEFAULT_EXCLUDES))
+        enabled = rules.get("enabled")
+        return cls(
+            max_file_bytes=max_bytes,
+            minimum_severity=Severity.parse(str(scan.get("minimum_severity", "low"))),
+            exclude=excluded,
+            enabled_rules=tuple(str(item) for item in enabled) if enabled is not None else None,
+        )
+
+
+STARTER_CONFIG = """[scan]
+max_file_bytes = 2097152
+minimum_severity = "low"
+exclude = [".git", ".venv", "__pycache__", "build", "dist", "node_modules"]
+
+[rules]
+enabled = [
+  "AAISA-SECRET-001",
+  "AAISA-PROMPT-001",
+  "AAISA-DEPENDENCY-001",
+  "AAISA-CONTAINER-001",
+  "AAISA-PROVENANCE-001",
+]
+"""