refactor: rename command files for namespace consistency

BREAKING CHANGE: All generic command names now prefixed with plugin namespace.
See CHANGELOG.md v7.0.0 for complete rename map.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

plugins/data-platform/commands/data-schema.md

@@ -0,0 +1,45 @@
+# /schema - Schema Exploration
+
+## Skills to Load
+- skills/mcp-tools-reference.md
+- skills/visual-header.md
+
+## Visual Output
+
+Display header: `DATA-PLATFORM - Schema Explorer`
+
+## Usage
+
+```
+/schema [table_name | data_ref]
+```
+
+## Workflow
+
+1. **Determine target**:
+   - DataFrame: show pandas schema via `describe`
+   - Database table: query via `pg_columns`
+   - No argument: list all tables and DataFrames
+
+2. **For DataFrames**: Show dtypes, null counts, sample values
+
+3. **For database tables**: Show columns, types, constraints, indexes
+
+4. **For PostGIS**: Include geometry type and SRID via `st_tables`
+
+## Examples
+
+```
+/schema                    # List all tables and DataFrames
+/schema customers          # Show table schema
+/schema sales_data         # Show DataFrame schema
+```
+
+## Required MCP Tools
+
+- `pg_tables` - List database tables
+- `pg_columns` - Get column info
+- `pg_schemas` - List schemas
+- `st_tables` - List PostGIS tables
+- `describe` - Get DataFrame info
+- `list_data` - List DataFrames