Enhance documentation with detailed findings from analysis report

- Add clustered vs isolated facility comparison to README
- Expand infrastructure insights with hyperscaler energy strategies
- Document additional database tables (opposition cases, IM3 projections, utility rates)
- Enhance research ideas with specific watershed names and grid saturation data
- Add data quality notes about EIA longitude corrections
- Reference loaded but unused tables for future analysis

database-tables.md

@@ -412,6 +412,93 @@ Tables are organized into four categories:
 
 ---
 
+### Other Tables
+
+#### `opposition_cases_geocoded`
+**Rows**: 18  
+**Purpose**: Geocoded community-opposition cases against data center builds
+
+**Key Columns**:
+- `case_id` (TEXT) - Unique identifier
+- `developer` (TEXT) - Proposed developer/operator
+- `investment_billions` (DOUBLE PRECISION) - Investment amount in billions
+- `outcome` (TEXT) - Case outcome (approved, rejected, pending)
+- `governance_response` (TEXT) - Government response
+- `latitude`, `longitude`, `geom`
+
+**Source**: Compiled from news archives
+
+**Notes**: Loaded but currently unused - see research-ideas.md for proposed analyses
+
+#### `census_tract_huc8_link`
+**Rows**: 806  
+**Purpose**: Tract↔HUC8 spatial overlap table
+
+**Key Columns**:
+- `geoid` (TEXT) - Census tract GEOID
+- `huc8` (TEXT) - HUC8 watershed code
+- `overlap_pct` (DOUBLE PRECISION) - Percentage of tract overlapping watershed
+
+**Notes**: Useful for downstream tract-level water-stress joins; limited to tracts containing data centers
+
+#### `im3_state_projected_moderate_50`
+**Rows**: 328  
+**Purpose**: PNNL IM3 projected data center siting (moderate growth, gravity weight 0.50)
+
+**Key Columns**:
+- `facility_id` (TEXT)
+- `state` (TEXT)
+- `cost_millions` (DOUBLE PRECISION)
+- `it_mw` (DOUBLE PRECISION) - IT load in megawatts
+- `cooling_water_demand_gal_per_day` (DOUBLE PRECISION)
+- `latitude`, `longitude`, `geom`
+
+**Source**: PNNL Integrated Multisector Multiscale Modeling (IM3)
+
+**Notes**: Loaded but unused - potential for forward-projection analysis
+
+#### `im3_projected_state_demand_summary`
+**Rows**: 31  
+**Purpose**: State-level rollup of IM3 projected facility counts, IT MW, and cooling demand
+
+**Key Columns**:
+- `state` (TEXT)
+- `facility_count` (INTEGER)
+- `total_it_mw` (DOUBLE PRECISION)
+- `total_cooling_demand_mgd` (DOUBLE PRECISION) - Million gallons per day
+
+**Source**: IM3 model outputs
+
+#### `utility_rate_tracker_2025_2028`
+**Rows**: 374  
+**Purpose**: Utility rate-increase tracker by provider × state × service type
+
+**Key Columns**:
+- `provider` (TEXT) - Utility provider name
+- `state` (TEXT)
+- `service_type` (TEXT)
+- `effective_date` (DATE)
+- `monthly_increase_dollars` (DOUBLE PRECISION)
+- `percent_increase` (DOUBLE PRECISION)
+
+**Source**: Utility rate tracker database
+
+**Notes**: Loaded but unused in demographic/energy analysis
+
+#### `energy_atlas_layers_catalog`
+**Rows**: ~5  
+**Purpose**: Metadata catalog of EIA layers ingested
+
+**Key Columns**:
+- `table_name` (TEXT)
+- `source_url` (TEXT)
+- `import_timestamp` (TIMESTAMP)
+- `row_count` (INTEGER)
+
+**Notes**: Created by `ingest_eia_energy_layers.py`
+
+---
+
 ## Commonly Used Joins
 
 ### Data Center to Demographics