feat(ci): add ghcr publish workflow and optimize triggers

Adds a new GitHub Action to publish a Docker image to GHCR on merges to main.

Also optimizes the triggers for the existing test and docker build workflows to only run when relevant files are changed, reducing unnecessary pipeline runs.

Author: angstwad

.github/workflows/test-app.yaml

@@ -2,6 +2,11 @@ on:
   pull_request:
     branches:
       - main
+    paths:
+      - 'src/**'
+      - 'tests/**'
+      - 'pyproject.toml'
+      - 'uv.lock'
 
 name: test app
 

.github/workflows/test-docker-build.yaml

@@ -2,6 +2,11 @@ on:
   pull_request:
     branches:
       - main
+    paths:
+      - 'Dockerfile'
+      - 'src/**'
+      - 'pyproject.toml'
+      - 'uv.lock'
 
 name: test dockerfile