Initial commit: CMM Report Analyzer

FastAPI app that parses CMM inspection reports (PDF/Excel/CSV),
computes SPC metrics (Cp/Cpk/Pp/Ppk, control limits, Shapiro-Wilk),
generates interactive Plotly charts, and provides AI-powered quality
summaries via Azure OpenAI with graceful fallback.

Includes 21 passing tests covering parsers, SPC calculations, and
API endpoints.

app/parsers/base.py

@@ -0,0 +1,55 @@
+from __future__ import annotations
+
+import re
+from abc import ABC, abstractmethod
+from pathlib import Path
+
+from app.parsers.models import ParsedReport
+
+# Fuzzy column-name patterns → canonical field name
+COLUMN_PATTERNS: dict[str, list[re.Pattern[str]]] = {
+    "feature_name": [
+        re.compile(r"feat|char|dimen|label|id|name|item", re.I),
+    ],
+    "nominal": [
+        re.compile(r"nom|target|blueprint|print", re.I),
+    ],
+    "tolerance_plus": [
+        re.compile(r"tol.*\+|upper.*tol|\+.*tol|usl|dev.*\+|pos.*tol", re.I),
+    ],
+    "tolerance_minus": [
+        re.compile(r"tol.*-|lower.*tol|-.*tol|lsl|dev.*-|neg.*tol", re.I),
+    ],
+    "actual": [
+        re.compile(r"actual|meas|value|result|reading", re.I),
+    ],
+    "deviation": [
+        re.compile(r"dev(?!.*tol)|diff|error|delta", re.I),
+    ],
+}
+
+
+def match_column(header: str) -> str | None:
+    """Return the canonical field name for a header string, or None."""
+    header = header.strip()
+    for field_name, patterns in COLUMN_PATTERNS.items():
+        for pat in patterns:
+            if pat.search(header):
+                return field_name
+    return None
+
+
+class CMMParser(ABC):
+    @abstractmethod
+    def parse(self, path: Path) -> ParsedReport: ...
+
+
+def get_parser(filename: str) -> CMMParser:
+    suffix = Path(filename).suffix.lower()
+    if suffix == ".pdf":
+        from app.parsers.pdf_parser import PDFParser
+        return PDFParser()
+    if suffix in (".xlsx", ".xls", ".csv"):
+        from app.parsers.excel_parser import ExcelParser
+        return ExcelParser()
+    raise ValueError(f"Unsupported file type: {suffix}")