feat(tradein): cian_state_parser shared utility + ScrapedLot Cian fields

- Add cian_state_parser.py: regex-based extractor for window._cianConfig push() entries,
  supports direct JSON, JSON.parse() escaped form, and optional demjson3 fallback
- Extend ScrapedLot in base.py with 13 Cian-specific fields (living_area_m2,
  bedrooms_count, balconies_count, loggias_count, description_minhash,
  cadastral_number, building_cadastral_number, phones, is_homeowner, is_pro_seller,
  bargain_allowed, sale_type, metro_stations)
- Add tests/test_cian_state_parser.py with 4 unit tests covering all parse strategies

tradein-mvp/backend/app/services/scrapers/base.py

@@ -93,6 +93,21 @@ class ScrapedLot(BaseModel):
     photo_urls: list[str] = Field(default_factory=list)
     raw_payload: dict[str, Any] | None = None
 
+    # Cian-specific extensions (Stage 2 of CianScraper v1)
+    living_area_m2: float | None = None
+    bedrooms_count: int | None = None
+    balconies_count: int | None = None
+    loggias_count: int | None = None
+    description_minhash: str | None = None
+    cadastral_number: str | None = None
+    building_cadastral_number: str | None = None
+    phones: list[dict] = Field(default_factory=list)
+    is_homeowner: bool | None = None
+    is_pro_seller: bool | None = None
+    bargain_allowed: bool | None = None
+    sale_type: str | None = None
+    metro_stations: list[dict] = Field(default_factory=list)
+
     def compute_dedup_hash(self) -> str:
         """SHA256(source + (source_id или source_url) + price_rub) — стабильный uniqueness key.
 

tradein-mvp/backend/app/services/scrapers/cian_state_parser.py

@@ -0,0 +1,93 @@
+"""Shared utility для извлечения Cian Redux state из _cianConfig.
+
+Pattern: window._cianConfig['<mfe>'].push({key:..., value:..., priority:..., filter:...})
+Used by SERP / detail / newbuilding / valuation scrapers.
+"""
+import json
+import logging
+import re
+from typing import Any
+
+logger = logging.getLogger(__name__)
+
+# Match both patterns Cian uses:
+#   1. window._cianConfig['mfe'].push({key:..., value:..., priority:..., filter:...})
+#   2. window._cianConfig['mfe'] = window._cianConfig['mfe'] || [];
+#      window._cianConfig['mfe'].push({...})
+_RE_CIAN_PUSH = re.compile(
+    r"window\._cianConfig\['(?P<mfe>[\w-]+)'\]"
+    r"(?:\.push\(\s*|"
+    r"\s*=\s*window\._cianConfig\['[\w-]+'\]\s*\|\|\s*\[\];\s*"
+    r"window\._cianConfig\['[\w-]+'\]\.push\(\s*)"
+    r"\{\s*key:\s*['\"](?P<key>\w+)['\"]\s*,\s*"
+    r"value:\s*(?P<value>.+?)\s*,\s*"
+    r"priority:",
+    re.DOTALL,
+)
+
+
+def extract_state(html: str, mfe: str, key: str = "initialState") -> dict[str, Any] | None:
+    """Extract state.value where _cianConfig[<mfe>] entry.key matches.
+
+    Returns parsed JSON dict, or None if not found / parse failed.
+    Logs warning at debug level on parse failure for diagnostics.
+    """
+    for match in _RE_CIAN_PUSH.finditer(html):
+        if match.group("mfe") != mfe or match.group("key") != key:
+            continue
+
+        value_str = match.group("value").strip()
+
+        # Strategy 1: direct JSON parse (value уже JSON-like)
+        try:
+            return json.loads(value_str)
+        except json.JSONDecodeError:
+            pass
+
+        # Strategy 2: JSON.parse("escaped string")
+        m_jp = re.match(r'JSON\.parse\(\s*"(.+?)"\s*\)\s*$', value_str, re.DOTALL)
+        if m_jp:
+            escaped = m_jp.group(1)
+            unescaped = (
+                escaped
+                .replace('\\"', '"')
+                .replace('\\\\', '\\')
+                .replace('\\n', '\n')
+                .replace('\\/', '/')
+            )
+            try:
+                return json.loads(unescaped)
+            except json.JSONDecodeError as exc:
+                logger.debug(
+                    "JSON.parse() unescape failed for mfe=%s key=%s: %s", mfe, key, exc
+                )
+                continue
+
+        # Strategy 3: raw JS object literal — try demjson3 (optional dep)
+        try:
+            import demjson3  # type: ignore[import-untyped]
+
+            return demjson3.decode(value_str)
+        except ImportError:
+            logger.debug(
+                "demjson3 not installed; cannot parse raw JS object for mfe=%s key=%s", mfe, key
+            )
+        except Exception as exc:
+            logger.debug("demjson3 parse failed for mfe=%s key=%s: %s", mfe, key, exc)
+
+    return None
+
+
+def extract_all_states(html: str) -> dict[str, dict[str, Any]]:
+    """Returns {mfe_name: {key: parsed_value}} for all push() entries.
+
+    Useful for discovery / debugging during scraper development.
+    """
+    result: dict[str, dict[str, Any]] = {}
+    for match in _RE_CIAN_PUSH.finditer(html):
+        mfe = match.group("mfe")
+        key = match.group("key")
+        parsed = extract_state(html, mfe, key)
+        if parsed is not None:
+            result.setdefault(mfe, {})[key] = parsed
+    return result

tradein-mvp/backend/tests/test_cian_state_parser.py

@@ -0,0 +1,46 @@
+"""Tests for cian_state_parser."""
+import pytest
+from app.services.scrapers.cian_state_parser import extract_state
+
+
+def test_extract_state_simple_json():
+    html = '''
+    <html><body>
+    <script>
+    window._cianConfig['frontend-serp'] = window._cianConfig['frontend-serp'] || [];
+    window._cianConfig['frontend-serp'].push({
+        key: 'initialState',
+        value: {"results": {"offers": [{"id": 1}]}},
+        priority: 1
+    });
+    </script>
+    </body></html>
+    '''
+    state = extract_state(html, mfe='frontend-serp', key='initialState')
+    assert state is not None
+    assert state['results']['offers'][0]['id'] == 1
+
+
+def test_extract_state_json_parse_form():
+    html = r'''
+    window._cianConfig['frontend-offer-card'].push({
+        key: 'defaultState',
+        value: JSON.parse("{\"offerData\":{\"offer\":{\"cianId\":123}}}"),
+        priority: 1
+    });
+    '''
+    state = extract_state(html, mfe='frontend-offer-card', key='defaultState')
+    assert state is not None
+    assert state['offerData']['offer']['cianId'] == 123
+
+
+def test_extract_state_missing_returns_none():
+    html = "<html></html>"
+    assert extract_state(html, mfe='frontend-serp') is None
+
+
+def test_extract_state_wrong_mfe_returns_none():
+    html = '''
+    window._cianConfig['other-mfe'].push({key: 'initialState', value: {}, priority: 1});
+    '''
+    assert extract_state(html, mfe='frontend-serp', key='initialState') is None