chore: bootstrap repository with governance docs

Initialize git, add Apache-2.0 LICENSE, .gitattributes (LF line
endings), AGENTS.md (entry points, stack, discovery order, baseline
checks), RUNBOOK.md (dev boot, prod deploy with overlay, ingestion,
failures, rollback, scaling notes), .env.prod.example with rotated
credential placeholders, and dev-only warnings on .env.example.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/utils/text_cleaning.py

@@ -0,0 +1,69 @@
+"""Conservative OCR text cleaning.
+
+Goals:
+- Drop hyphenation across line breaks (``инвен-\\nтарный`` -> ``инвентарный``).
+- Collapse runs of whitespace.
+- Strip control chars.
+- Preserve all non-letter characters that may carry meaning in legacy/technical
+  documents: digits, punctuation, slashes, dashes, dots, parentheses, etc.
+
+We do NOT lowercase, transliterate, or strip punctuation here. ``normalize_for_search``
+produces a more aggressive form for indexing, but the original ``text`` is always
+kept untouched for citation/display.
+"""
+
+from __future__ import annotations
+
+import re
+import unicodedata
+
+_CONTROL_CHARS = re.compile(r"[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]")
+_SOFT_HYPHEN = "­"
+_MULTI_WS = re.compile(r"[ \t ]+")
+_MULTI_NL = re.compile(r"\n{3,}")
+_HYPHEN_LINEBREAK = re.compile(r"(\w)[-‐‑‒–]\n(\w)")
+_TRAILING_WS = re.compile(r"[ \t]+\n")
+
+
+def clean_ocr_text(text: str) -> str:
+    if not text:
+        return ""
+    # Normalize unicode (NFC) to merge combining marks.
+    text = unicodedata.normalize("NFC", text)
+    text = text.replace(_SOFT_HYPHEN, "")
+    text = _CONTROL_CHARS.sub("", text)
+    text = _HYPHEN_LINEBREAK.sub(r"\1\2", text)
+    text = _TRAILING_WS.sub("\n", text)
+    text = _MULTI_WS.sub(" ", text)
+    text = _MULTI_NL.sub("\n\n", text)
+    return text.strip()
+
+
+_PUNCT_RUN = re.compile(r"[^\w\s/\-.,№#:()\[\]]+", flags=re.UNICODE)
+_WS_RUN = re.compile(r"\s+")
+
+
+def normalize_for_search(text: str) -> str:
+    """Lowercase + light normalization for full-text indexing.
+
+    Preserves digits, alphanumerics, slashes, dashes, dots, commas, ``№``, ``#``,
+    colons and brackets - all of which appear in document/serial/standard codes.
+    """
+    if not text:
+        return ""
+    text = clean_ocr_text(text)
+    text = text.lower()
+    text = _PUNCT_RUN.sub(" ", text)
+    text = _WS_RUN.sub(" ", text)
+    return text.strip()
+
+
+def looks_garbled(text: str, threshold: float = 0.35) -> bool:
+    """Heuristic: ratio of non-alphanumeric, non-whitespace chars."""
+    if not text:
+        return False
+    total = len(text)
+    if total < 20:
+        return False
+    bad = sum(1 for c in text if not (c.isalnum() or c.isspace() or c in ".,;:!?-/()[]№#"))
+    return (bad / total) > threshold