Pinscope open-source core

Agentic schematic validation: datasheet extraction via Claude Console
Skills, netlist/BOM design graph, per-IC direct datasheet review with
page citations, capacitor derating, Next.js report UI.

Extracted from the Pinscope cloud codebase. Auth and billing live in the
private gateway repo behind stable seams (billing_hook.py, adapter files
listed in CLAUDE.md).

backend/_version.py

@@ -0,0 +1,38 @@
+"""Pinscope app version, sourced from frontend/content/changelog.md.
+
+The changelog is the single source of truth for the user-facing version.
+The Dockerfile copies it into the image at /app/changelog.md; locally we
+fall back to the in-repo path.
+"""
+from __future__ import annotations
+
+import re
+from functools import lru_cache
+from pathlib import Path
+
+
+def _candidate_paths() -> list[Path]:
+    here = Path(__file__).resolve()
+    return [
+        Path("/app/changelog.md"),
+        here.parent.parent / "frontend" / "content" / "changelog.md",
+    ]
+
+
+_VERSION_RE = re.compile(r"^##\s+(\d+\.\d+\.\d+)\b", re.MULTILINE)
+
+
+@lru_cache(maxsize=1)
+def get_pinscope_version() -> str:
+    for path in _candidate_paths():
+        try:
+            text = path.read_text(encoding="utf-8")
+        except (FileNotFoundError, OSError):
+            continue
+        m = _VERSION_RE.search(text)
+        if m:
+            return m.group(1)
+    return "unknown"
+
+
+PINSCOPE_VERSION = get_pinscope_version()