feat(docker-runtime): unified Debian-based images, dynamic path resolution & enhanced UNO/LibreOffice handling (#4880)

# Description of Changes

### What was changed

This PR introduces a major refinement to the Docker runtime, system path
resolution, conversion tooling, and integration logic across the
codebase. Key improvements include:

- Migration of **Dockerfile**, **Dockerfile.fat** to a unified
Debian-based environment.
- Introduction of **RuntimePathConfig** enhancements to dynamically
resolve:
  - `weasyprint`, `unoconvert`, `calibre`, `ocrmypdf`, `soffice`
  - Tesseract `tessdata` paths with Docker-aware defaults.
- Support for **UNO server (unoserver/unoconvert)** as primary document
converter with automatic fallback to `soffice`.
- Isolation of Python environments for WeasyPrint and UNO tooling.
- Updated controllers and services to correctly inject
`RuntimePathConfig`.
- Improved process execution logic in converters and OCR handling.
- Major updates to `init.sh` and `init-without-ocr.sh`:
  - Unified environment initialization
  - Proper UID/GID remapping
  - Safer permissions handling
  - Automatic Tesseract path detection
  - Reliable startup of headless LibreOffice + Xvfb + UNO server
- Full test suite updates:
  - Adaptation to new conversion paths
  - Mocking of UNO and LibreOffice commands
  - More robust Docker test logic
- Updated example docker-compose files referencing GHCR test images.
- Expanded configuration schema for new operations paths.

### Why the change was made

These changes address long-standing issues around:

- Inconsistent or missing binary paths between image variants.
- Reduced reliability of document conversions (UNO vs. soffice).
- Lack of uniform runtime initialization across Docker images.
- Repetitive environment setup logic split across multiple scripts.
- Fragile test scenarios tied to Alpine-based images.

Switching to a unified Debian-based runtime significantly improves:

- Compatibility with LibreOffice, Calibre, WebEngine and graphics stack.
- UNO stability for document conversions.
- Tesseract deterministic behavior.
- Debuggability and reliability of CI/CD Docker-based tests.

The improvements to `RuntimePathConfig` ensure all system binaries are
fully configurable and correctly detected at runtime.

---

## Checklist

### General

- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [x] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [x] I have performed a self-review of my own code
- [x] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [x] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

exampleYmlFiles/docker-compose-latest-fat-endpoints-disabled.yml

@@ -1,8 +1,8 @@
-
 services:
   stirling-pdf:
     container_name: Stirling-PDF-Fat-Disable-Endpoints
-    image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest-fat
+    # image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest-fat
+    image: ghcr.io/stirling-tools/stirling-pdf-test:fat
     deploy:
       resources:
         limits:

exampleYmlFiles/docker-compose-latest-fat-security.yml

@@ -1,7 +1,8 @@
 services:
   stirling-pdf:
     container_name: Stirling-PDF-Security-Fat
-    image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest-fat
+    # image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest-fat
+    image: ghcr.io/stirling-tools/stirling-pdf-test:fat
     deploy:
       resources:
         limits:

exampleYmlFiles/docker-compose-latest-security-with-sso.yml

@@ -1,7 +1,8 @@
 services:
   stirling-pdf:
     container_name: Stirling-PDF-Security
-    image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest
+    # image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest
+    image: ghcr.io/stirling-tools/stirling-pdf-test:latest
     deploy:
       resources:
         limits:
@@ -22,9 +23,9 @@ services:
       SECURITY_ENABLELOGIN: "true"
       SECURITY_OAUTH2_ENABLED: "true"
       SECURITY_OAUTH2_AUTOCREATEUSER: "true" # This is set to true to allow auto-creation of non-existing users in Stirling-PDF
-      SECURITY_OAUTH2_ISSUER: "https://accounts.google.com"  # Change with any other provider that supports OpenID Connect Discovery (/.well-known/openid-configuration) end-point
+      SECURITY_OAUTH2_ISSUER: "https://accounts.google.com" # Change with any other provider that supports OpenID Connect Discovery (/.well-known/openid-configuration) end-point
       SECURITY_OAUTH2_CLIENTID: "<YOUR CLIENT ID>.apps.googleusercontent.com" # Client ID from your provider
-      SECURITY_OAUTH2_CLIENTSECRET: "<YOUR CLIENT SECRET>"  # Client Secret from your provider
+      SECURITY_OAUTH2_CLIENTSECRET: "<YOUR CLIENT SECRET>" # Client Secret from your provider
       SECURITY_OAUTH2_SCOPES: "openid,profile,email" # Expected OAuth2 Scope
       SECURITY_OAUTH2_USEASUSERNAME: "email" # Default is 'email'; custom fields can be used as the username
       SECURITY_OAUTH2_PROVIDER: "google" # Set this to your OAuth provider's name, e.g., 'google' or 'keycloak'

exampleYmlFiles/docker-compose-latest-security.yml

@@ -1,7 +1,8 @@
 services:
   stirling-pdf:
     container_name: Stirling-PDF-Security
-    image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest
+    # image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest
+    image: ghcr.io/stirling-tools/stirling-pdf-test:latest
     deploy:
       resources:
         limits:

exampleYmlFiles/docker-compose-latest-ultra-lite-security.yml

@@ -1,7 +1,8 @@
 services:
   stirling-pdf:
     container_name: Stirling-PDF-Ultra-Lite-Security
-    image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest-ultra-lite
+    # image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest-ultra-lite
+    image: ghcr.io/stirling-tools/stirling-pdf-test:ultra-lite
     deploy:
       resources:
         limits:

exampleYmlFiles/docker-compose-latest-ultra-lite.yml

@@ -1,7 +1,8 @@
 services:
   stirling-pdf:
     container_name: Stirling-PDF-Ultra-Lite
-    image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest-ultra-lite
+    # image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest-ultra-lite
+    image: ghcr.io/stirling-tools/stirling-pdf-test:ultra-lite
     deploy:
       resources:
         limits:

exampleYmlFiles/docker-compose-latest.yml

@@ -1,7 +1,8 @@
 services:
   stirling-pdf:
     container_name: Stirling-PDF
-    image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest
+    # image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest
+    image: ghcr.io/stirling-tools/stirling-pdf-test:latest
     deploy:
       resources:
         limits:

exampleYmlFiles/test_cicd.yml

@@ -1,7 +1,8 @@
 services:
   stirling-pdf:
     container_name: Stirling-PDF-Security-Fat-with-login
-    image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest-fat
+    # image: docker.stirlingpdf.com/stirlingtools/stirling-pdf:latest-fat
+    image: ghcr.io/stirling-tools/stirling-pdf-test:fat
     deploy:
       resources:
         limits: