docs(docker): add --name mcpg to the docker run examples

Give the container a stable name in both the GHCR pull-and-run block
(README) and the build-from-source block (installation.md), so operators
can address it by name (docker logs mcpg, docker stop mcpg).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0122yLZLJ8t4W43sdN6BmTZc

Author: claude

README.md

@@ -96,7 +96,7 @@ like `:0.6.5`):
 
 ```bash
 docker pull ghcr.io/devopam/mcpg:latest
-docker run --rm -p 8000:8000 \
+docker run --rm --name mcpg -p 8000:8000 \
     -e MCPG_DATABASE_URL=postgresql://user:pass@host:5432/db \
     -e MCPG_ACCESS_MODE=read-only \
     ghcr.io/devopam/mcpg:latest

docs/installation.md

@@ -54,7 +54,7 @@ mcpg --version
 
 ```bash
 docker build -t mcpg https://github.com/devopam/MCPg.git
-docker run --rm -p 8000:8000 \
+docker run --rm --name mcpg -p 8000:8000 \
     -e MCPG_DATABASE_URL=postgresql://user:pass@host:5432/db \
     -e MCPG_ACCESS_MODE=read-only \
     mcpg