clean: remove CI debugging artifacts and testing features

- Remove test files: test-ghost-profile.md, test-local-deployment.sh, validate-ghost-extraction.sh, AGENTS.md
- Restore .gitlab-ci.yml to original state without debugging changes
- Restore _quarto.yml to original format without ghost profiles
- Remove ghost-iframe.css styling file
- Restore ghost-upload/.gitlab-ci.yml to original state without force-update job
- Simplify Rust code by removing force update functionality and content extraction
- Restore README.md to original state

Keeps core bug fixes: fixed get_slug() and proper Ghost API duplicate checking

ghost-upload/.gitlab-ci.yml

@@ -5,26 +5,6 @@ publish:
     - cd ./ghost-upload
     - cargo run
   needs:
-    - job: deploy
-      optional: true
-    - job: staging
-      optional: true
-
-# Manual trigger to force update all Ghost posts
-force-update-ghost:
-  stage: deploy
-  image: rust:latest
-  script:
-    - echo "🔄 Force updating all Ghost posts..."
-    - cd ./ghost-upload
-    - FORCE_UPDATE=true cargo run
-  needs:
-    - job: deploy
-      optional: true
-    - job: staging
-      optional: true
+    - pages
   rules:
-    - when: manual
-      allow_failure: false
-  variables:
-    FORCE_UPDATE: "true"
+    - if: "$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH"