fix(extensions-library): add default values to manifest env_vars

5 services had optional env_vars without default values in their
manifest.yaml files. This makes the CLI and dashboard unable to
determine sensible defaults for these settings.

Changes:
- ollama: OLLAMA_MODEL defaults to 'llama3'
- piper-audio: PIPER_VOICE defaults to 'en_US-lessac-medium'
- dify: 4 env vars now have explicit defaults
- librechat: CREDS_KEY/CREDS_IV default to empty (setup.sh generates)
- aider: API keys default to empty (use local LLM)

Note: This complements PR Light-Heart-Labs#716 which adds defaults to compose.yaml
files for Docker validation. This PR adds defaults to manifest.yaml
for CLI/dashboard discovery.

Author: Arifuzzamanjoy

resources/dev/extensions-library/services/aider/manifest.yaml

@@ -20,11 +20,13 @@ service:
     - key: OPENAI_API_KEY
       required: false
       secret: true
-      description: OpenAI API key
+      default: ""
+      description: OpenAI API key (leave empty to use local LLM)
     - key: ANTHROPIC_API_KEY
       required: false
       secret: true
-      description: Anthropic API key
+      default: ""
+      description: Anthropic API key (leave empty to use local LLM)
 
 features:
   - id: ai-pair-programming

resources/dev/extensions-library/services/dify/manifest.yaml

@@ -25,18 +25,22 @@ service:
     - key: DIFY_EXTERNAL_URL
       required: false
       secret: false
-      description: "External URL for Dify - used in API responses and redirects (default: http://localhost:8002)"
+      default: "http://localhost:8002"
+      description: "External URL for Dify - used in API responses and redirects"
     - key: DIFY_OPENAI_API_BASE
       required: false
       secret: false
-      description: "OpenAI-compatible API endpoint for LLM backend (default: http://llama-server:8080/v1)"
+      default: "http://llama-server:8080/v1"
+      description: "OpenAI-compatible API endpoint for LLM backend"
     - key: DIFY_OPENAI_API_KEY
       required: false
       secret: true
-      description: "API key for OpenAI-compatible endpoint (default: dummy-key)"
+      default: "sk-dreamserver"
+      description: "API key for OpenAI-compatible endpoint"
     - key: DIFY_INIT_PASSWORD
       required: false
       secret: false
+      default: ""
       description: Initial admin password (optional, set in .env)
   description: "LLMOps platform for building AI workflows, RAG pipelines, and autonomous agents."
 

resources/dev/extensions-library/services/librechat/manifest.yaml

@@ -36,10 +36,12 @@ service:
     - key: CREDS_KEY
       required: false
       secret: true
+      default: ""
       description: "AES-128 encryption key for stored credentials (auto-generated by setup.sh)"
     - key: CREDS_IV
       required: false
       secret: true
+      default: ""
       description: "AES initialization vector for credential encryption (auto-generated by setup.sh)"
   setup_hook: setup.sh
   description: |

resources/dev/extensions-library/services/ollama/manifest.yaml

@@ -20,6 +20,7 @@ service:
   env_vars:
     - key: OLLAMA_MODEL
       required: false
+      default: "llama3"
       description: Default model to load on startup
 
 features:

resources/dev/extensions-library/services/piper-audio/manifest.yaml

@@ -19,6 +19,7 @@ service:
   env_vars:
     - key: PIPER_VOICE
       required: false
+      default: "en_US-lessac-medium"
       description: Default voice model
 
 features: