Add adjustable context size, custom chatbot name, and cat icon for AI chat

Settings > AI tab now includes context size slider (2048–131072) with VRAM
estimate and a chatbot name field. ChatService reads both dynamically instead
of hardcoding num_ctx=16384 and "Purrse AI". Chat panel FAB and empty state
use mdi-cat icon to match the rest of the app.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/Purrse.Api/Services/AiCategorizationService.cs

@@ -67,13 +67,14 @@ public class AiCategorizationService : IAiCategorizationService
         if (settings == null)
         {
             return new AiCategorizationSettingsResponse(
-                false, "http://localhost:11434", "llama3.1:8b", 0.7, 30, true, null, null);
+                false, "http://localhost:11434", "llama3.1:8b", 0.7, 30, true, null, null, 16384, null);
         }
 
         return new AiCategorizationSettingsResponse(
             settings.IsEnabled, settings.OllamaUrl, settings.ModelName,
             settings.ConfidenceThreshold, settings.TimeoutSeconds, settings.UpdatePayeeDefaults,
-            settings.SystemPrompt, settings.UserPromptTemplate);
+            settings.SystemPrompt, settings.UserPromptTemplate,
+            settings.ChatContextSize, settings.ChatBotName);
     }
 
     public async Task<AiCategorizationSettingsResponse> UpdateSettingsAsync(Guid userId, UpdateAiCategorizationSettingsRequest request)
@@ -98,6 +99,8 @@ public class AiCategorizationService : IAiCategorizationService
         settings.UpdatePayeeDefaults = request.UpdatePayeeDefaults;
         settings.SystemPrompt = string.IsNullOrWhiteSpace(request.SystemPrompt) ? null : request.SystemPrompt;
         settings.UserPromptTemplate = string.IsNullOrWhiteSpace(request.UserPromptTemplate) ? null : request.UserPromptTemplate;
+        settings.ChatContextSize = request.ChatContextSize;
+        settings.ChatBotName = string.IsNullOrWhiteSpace(request.ChatBotName) ? null : request.ChatBotName;
         settings.UpdatedAt = DateTime.UtcNow;
 
         await _db.SaveChangesAsync();
@@ -105,7 +108,8 @@ public class AiCategorizationService : IAiCategorizationService
         return new AiCategorizationSettingsResponse(
             settings.IsEnabled, settings.OllamaUrl, settings.ModelName,
             settings.ConfidenceThreshold, settings.TimeoutSeconds, settings.UpdatePayeeDefaults,
-            settings.SystemPrompt, settings.UserPromptTemplate);
+            settings.SystemPrompt, settings.UserPromptTemplate,
+            settings.ChatContextSize, settings.ChatBotName);
     }
 
     public async Task<OllamaConnectionTestResponse> TestConnectionAsync(Guid userId)

src/Purrse.Api/Services/ChatService.cs

@@ -113,6 +113,8 @@ public class ChatService : IChatService
         var settings = await _db.AiCategorizationSettings.FirstOrDefaultAsync(s => s.UserId == userId);
         var ollamaUrl = settings?.OllamaUrl ?? "http://localhost:11434";
         var modelName = settings?.ModelName ?? "llama3.1:8b";
+        var chatContextSize = settings?.ChatContextSize ?? 16384;
+        var chatBotName = settings?.ChatBotName;
 
         // Save user message
         var userMessage = new ChatMessage
@@ -130,10 +132,15 @@ public class ChatService : IChatService
         var ollamaMessages = new List<OllamaToolMessage>();
 
         // System prompt
+        var systemPrompt = string.Format(SystemPromptTemplate, DateTime.UtcNow.ToString("yyyy-MM-dd"));
+        if (!string.IsNullOrWhiteSpace(chatBotName))
+        {
+            systemPrompt += $"\nYour name is {chatBotName}.";
+        }
         ollamaMessages.Add(new OllamaToolMessage
         {
             Role = "system",
-            Content = string.Format(SystemPromptTemplate, DateTime.UtcNow.ToString("yyyy-MM-dd"))
+            Content = systemPrompt
         });
 
         // Last 20 conversation messages
@@ -199,7 +206,7 @@ public class ChatService : IChatService
                 Messages = ollamaMessages,
                 Stream = false,
                 Tools = tools,
-                Options = new OllamaRequestOptions { NumCtx = 16384 }
+                Options = new OllamaRequestOptions { NumCtx = chatContextSize }
             };
 
             var response = await CallOllamaAsync(ollamaUrl, ollamaRequest);
@@ -272,7 +279,7 @@ public class ChatService : IChatService
                         Messages = ollamaMessages,
                         Stream = false,
                         Tools = null, // drop tools so the model focuses on the page data
-                        Options = new OllamaRequestOptions { NumCtx = 16384 }
+                        Options = new OllamaRequestOptions { NumCtx = chatContextSize }
                     };
                     var retryResponse = await CallOllamaAsync(ollamaUrl, retryRequest);
                     rawContent = retryResponse?.Message?.Content;

src/Purrse.Core/DTOs/AiCategorizationDtos.cs

@@ -11,7 +11,9 @@ public record AiCategorizationSettingsResponse(
     int TimeoutSeconds,
     bool UpdatePayeeDefaults,
     string? SystemPrompt,
-    string? UserPromptTemplate);
+    string? UserPromptTemplate,
+    int ChatContextSize,
+    string? ChatBotName);
 
 public record UpdateAiCategorizationSettingsRequest(
     bool IsEnabled,
@@ -21,7 +23,9 @@ public record UpdateAiCategorizationSettingsRequest(
     int TimeoutSeconds,
     bool UpdatePayeeDefaults,
     string? SystemPrompt,
-    string? UserPromptTemplate);
+    string? UserPromptTemplate,
+    int ChatContextSize,
+    string? ChatBotName);
 
 // Connection test
 public record OllamaConnectionTestResponse(

src/Purrse.Core/Models/AiCategorizationSettings.cs

@@ -12,6 +12,8 @@ public class AiCategorizationSettings
     public bool UpdatePayeeDefaults { get; set; } = true;
     public string? SystemPrompt { get; set; }
     public string? UserPromptTemplate { get; set; }
+    public int ChatContextSize { get; set; } = 16384;
+    public string? ChatBotName { get; set; }
     public DateTime UpdatedAt { get; set; } = DateTime.UtcNow;
 
     public User User { get; set; } = null!;

src/Purrse.Data/Configurations/AiCategorizationSettingsConfiguration.cs

@@ -14,6 +14,7 @@ public class AiCategorizationSettingsConfiguration : IEntityTypeConfiguration<Ai
         builder.Property(s => s.ModelName).HasMaxLength(100);
         builder.Property(s => s.SystemPrompt).HasMaxLength(4000);
         builder.Property(s => s.UserPromptTemplate).HasMaxLength(4000);
+        builder.Property(s => s.ChatBotName).HasMaxLength(100);
 
         builder.HasOne(s => s.User)
             .WithOne(u => u.AiCategorizationSettings)

src/Purrse.Data/Migrations/20260213192005_AddChatSettings.cs

@@ -0,0 +1,40 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Purrse.Data.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddChatSettings : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "ChatBotName",
+                table: "ai_categorization_settings",
+                type: "character varying(100)",
+                maxLength: 100,
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "ChatContextSize",
+                table: "ai_categorization_settings",
+                type: "integer",
+                nullable: false,
+                defaultValue: 0);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "ChatBotName",
+                table: "ai_categorization_settings");
+
+            migrationBuilder.DropColumn(
+                name: "ChatContextSize",
+                table: "ai_categorization_settings");
+        }
+    }
+}

src/Purrse.Data/Migrations/PurrseDbContextModelSnapshot.cs

@@ -91,6 +91,13 @@ namespace Purrse.Data.Migrations
                         .ValueGeneratedOnAdd()
                         .HasColumnType("uuid");
 
+                    b.Property<string>("ChatBotName")
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<int>("ChatContextSize")
+                        .HasColumnType("integer");
+
                     b.Property<double>("ConfidenceThreshold")
                         .HasColumnType("double precision");