Fix gemma dependency to use crimson-knight/gemma

Changed gemma dependency from amberframework/gemma to crimson-knight/gemma
in both the hardcoded new.cr and template file.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: crimson-knight

src/amber_cli/commands/new.cr

@@ -174,7 +174,7 @@ module AmberCLI::Commands
 
           # File uploads (optional)
           gemma:
-            github: amberframework/gemma
+            github: crimson-knight/gemma
 
           # Database adapters (all required by Grant at compile time)
           pg:

src/amber_cli/templates/app/shard.yml.ecr

@@ -29,7 +29,7 @@ dependencies:
 
   # File uploads (optional)
   gemma:
-    github: amberframework/gemma
+    github: crimson-knight/gemma
 
   # Database adapters (all required by Grant at compile time)
   pg: