docs: CHANGELOG + PROJECT.md for opportunity_score integration

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -7,6 +7,13 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 ## [Unreleased]
 
 ### Added
+- **Opportunity Score integration** — second scoring dimension (`Marktpotenzial`) now visible in city and country articles:
+  - **SQL chain**: `dim_cities` now carries `geoname_id` (from the existing GeoNames LEFT JOIN); threaded through `city_market_profile` → `pseo_city_costs_de` which LEFT JOINs `location_opportunity_profile` on `(country_code, geoname_id)`; `pseo_country_overview` gains `avg_opportunity_score`, `top_opportunity_score`, `top_opportunity_slugs`, `top_opportunity_names`
+  - **71.4% match rate** — 3,350 of 4,693 cities matched to a GeoNames `geoname_id`; unmatched cities gracefully show no Opportunity Score
+  - **City articles** (`city-cost-de.md.jinja`) — `{% if opportunity_score %}` guard adds: 5th stats-strip item with green/amber/red color coding (≥65/≥40/<40), contextual intro sentence explaining the score interplay, table row in Market Overview, score explainer FAQ (DE + EN)
+  - **Country overview articles** (`country-overview.md.jinja`) — adds: `avg_opportunity_score` as 5th stats-strip item, opportunity interplay paragraph in market landscape section, "Top Locations by Investment Potential" table (distinct from top Market Score cities), score explainer FAQ (DE + EN)
+  - **CSS**: stats-strip changed from `repeat(4, 1fr)` to `repeat(auto-fit, minmax(140px, 1fr))` — supports 4-item country and 5-item city strips without layout breakage
+
 - **Pipeline Console admin section** — full operational visibility into the data engineering pipeline at `/admin/pipeline/`:
   - **Overview tab** — extraction status grid (one card per workflow with status dot, schedule, last-run timestamp, error preview), serving table row counts from `_serving_meta.json`, landing zone file stats (per-source file count + total size)
   - **Extractions tab** — filterable, paginated run history table from `.state.sqlite` (extractor + status dropdowns, HTMX live filter); stale "running" row detection (amber highlight) with "Mark Failed" button; "Run All Extractors" button enqueues `run_extraction` task