Split native Periscope (periscope/src) from inherited PinScope (periscope/dependency).

Keep validate.py and the finding engine as-is. AGPL LICENSE stays at the repo root.
Docker overlays dependency then src. Do not delete the inherited tree.

tests/test_datasheet_excerpt_tool.py

@@ -2,6 +2,8 @@
 
 from __future__ import annotations
 
+from tests.paths import SIMPLE_PROJECT, TAXONOMY
+
 import json
 from pathlib import Path
 
@@ -19,7 +21,7 @@ from backend.periscopex.validation_tools import (
 from backend.services.llm.types import PdfBlock
 from backend.services.validation import _signal_neighbors
 
-GRAPH = Path(__file__).resolve().parent.parent / "simple_project" / "design_graph.json"
+GRAPH = SIMPLE_PROJECT / "design_graph.json"
 IC_MPNS = {
     "U1": "SPX3819M5-L-3-3/TR",
     "U2": "CH340E",