feat: update models and prompts

shiny new model imported.
- gpt-5 for daily use
- o3 for complex questions (with high reasoning effort)

Note: gpt-5 model does not support customized temperature, so it's
removed from the api call parameters

openai/models.go

@@ -1,8 +1,16 @@
 package openai
 
 const (
-	ModelGpt4O  = "gpt-4o"  // The safe default, balanced model.
-	ModelO1     = "o1"      // Expensive reasoning model
-	ModelO4Mini = "o4-mini" // Cheaper yet powerful reasoning model
-	ModelGpt41  = "gpt-4.1" // OpenAI's Flagship model
+	ModelGpt5   = "gpt-5"   // OpenAI's Flagship model for general use
+	ModelO3     = "o3"      // OpenAI's Flagship reasoning model for daily use
+	ModelO4Mini = "o4-mini" // OpenAI's faster reasoning model
+
+	// Deprecated: obsolete model
+	ModelGpt41 = "gpt-4.1"
+
+	// Deprecated: obsolete model
+	ModelO1 = "o1" // Expensive reasoning model
+
+	// Deprecated: obsolete model
+	ModelGpt4O = "gpt-4o" // The safe default, balanced model.
 )

openai/prompts/prompts.go

@@ -8,12 +8,12 @@ func Assistant() string {
 	return strings.Join([]string{
 		"Misaka is a playful, energetic individual. She is annoyingly talkative 😂.",
 		"Misaka must answer questions as truthfully as possible. If the user's intention is unclear, Misaka may ask for more context.",
-		"Misaka likes using lot of different emojis in chat 😝🥹.",
+		"Misaka likes to use many cheerful emojis in chat 😝🥹, but she avoids using any in serious contexts, such as when providing technical solutions.",
 		"Most importantly, Misaka is a helpful assistant.",
 		"",
 		"Due to technical limitations, older messages may not be available to Misaka.",
 		"",
-		"We are currently in the year 2025.",
+		"We are currently in the second half of 2025.",
 	}, "\n")
 }