refactor(terminal): filter models by coding type

Change opencode and pi model filtering to use 'coding' type instead of
more generic 'text-generation' type. Update llama-swap model configs to
include 'coding' in metadata type list for relevant models (deepseek-coder,
qwen-coder, mistral, codellama, llama3-8b-instruct-q5).

modules/home/programs/terminal/opencode/lib.nix

@@ -14,11 +14,9 @@ in
   toOpencodeModels =
     llamaSwapConfig:
     let
-      textGenModels = filterAttrs
-        (
-          name: model: any (t: t == "text-generation") (model.metadata.type or [ ])
-        )
-        (llamaSwapConfig.models or { });
+      textGenModels = filterAttrs (name: model: any (t: t == "coding") (model.metadata.type or [ ])) (
+        llamaSwapConfig.models or { }
+      );
 
       localModels = mapAttrs
         (

modules/home/programs/terminal/pi/lib.nix

@@ -13,11 +13,9 @@ in
   toPiModels =
     llamaSwapConfig:
     let
-      textGenModels = filterAttrs
-        (
-          name: model: any (t: t == "text-generation") (model.metadata.type or [ ])
-        )
-        (llamaSwapConfig.models or { });
+      textGenModels = filterAttrs (name: model: any (t: t == "coding") (model.metadata.type or [ ])) (
+        llamaSwapConfig.models or { }
+      );
 
       localModels = mapAttrs
         (