feat: massive overhaul to manage costs (#103)

### Explanation

_No response_

### Issue

Closes #102

### Attestations

- [ ] I have read and agree to the [Code of Conduct](https://docs.nhcarrigan.com/community/coc/)
- [ ] I have read and agree to the [Community Guidelines](https://docs.nhcarrigan.com/community/guide/).
- [ ] My contribution complies with the [Contributor Covenant](https://docs.nhcarrigan.com/dev/covenant/).

### Dependencies

- [ ] I have pinned the dependencies to a specific patch version.

### Style

- [ ] I have run the linter and resolved any errors.
- [ ] My pull request uses an appropriate title, matching the conventional commit standards.
- [ ] My scope of feat/fix/chore/etc. correctly matches the nature of changes in my pull request.

### Tests

- [ ] My contribution adds new code, and I have added tests to cover it.
- [ ] My contribution modifies existing code, and I have updated the tests to reflect these changes.
- [ ] All new and existing tests pass locally with my changes.
- [ ] Code coverage remains at or above the configured threshold.

### Documentation

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### Versioning

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Reviewed-on: #103
Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Co-committed-by: Naomi Carrigan <commits@nhcarrigan.com>

src-tauri/src/wsl_bridge.rs

@@ -9,12 +9,13 @@ use tempfile::NamedTempFile;
 use std::os::windows::process::CommandExt;
 
 use crate::achievements::{get_achievement_info, AchievementUnlockedEvent};
+use crate::commands::record_cost;
 use crate::config::ClaudeStartOptions;
-use crate::stats::{StatsUpdateEvent, UsageStats};
+use crate::stats::{calculate_cost, StatsUpdateEvent, UsageStats};
 use crate::types::{
-    CharacterState, ClaudeMessage, ConnectionEvent, ConnectionStatus, ContentBlock, OutputEvent,
-    PermissionPromptEvent, QuestionOption, SessionEvent, StateChangeEvent, UserQuestionEvent,
-    WorkingDirectoryEvent,
+    CharacterState, ClaudeMessage, ConnectionEvent, ConnectionStatus, ContentBlock, MessageCost,
+    OutputEvent, PermissionPromptEvent, QuestionOption, SessionEvent, StateChangeEvent,
+    UserQuestionEvent, WorkingDirectoryEvent,
 };
 use parking_lot::RwLock;
 
@@ -534,6 +535,7 @@ fn handle_stderr(
                         content: line,
                         tool_name: None,
                         conversation_id: conversation_id.clone(),
+                        cost: None,
                     },
                 );
             }
@@ -586,17 +588,57 @@ fn process_json_line(
             let mut state = CharacterState::Typing;
             let mut tool_name = None;
 
+            // Collect all tool names in this message for token attribution
+            let tools_in_message: Vec<String> = message
+                .content
+                .iter()
+                .filter_map(|block| match block {
+                    ContentBlock::ToolUse { name, .. } => Some(name.clone()),
+                    _ => None,
+                })
+                .collect();
+
+            // Track message cost for display
+            let mut message_cost: Option<MessageCost> = None;
+
             // Only update stats if we have usage information
             if let Some(usage) = &message.usage {
                 if let Some(model) = &message.model {
+                    // Calculate cost for historical tracking
+                    let cost_usd = calculate_cost(usage.input_tokens, usage.output_tokens, model);
+
+                    // Store cost for later use in output events
+                    message_cost = Some(MessageCost {
+                        input_tokens: usage.input_tokens,
+                        output_tokens: usage.output_tokens,
+                        cost_usd,
+                    });
+
                     // Batch all stats updates in a single write lock
                     {
                         let mut stats_guard = stats.write();
                         stats_guard.increment_messages();
                         stats_guard.add_usage(usage.input_tokens, usage.output_tokens, model);
                         stats_guard.get_session_duration();
+
+                        // Attribute tokens to tools if any tools were used in this message
+                        if !tools_in_message.is_empty() {
+                            let per_tool_input = usage.input_tokens / tools_in_message.len() as u64;
+                            let per_tool_output = usage.output_tokens / tools_in_message.len() as u64;
+                            for tool in &tools_in_message {
+                                stats_guard.add_tool_tokens(tool, per_tool_input, per_tool_output);
+                            }
+                        }
                     }
 
+                    // Record to historical cost tracking
+                    let app_clone = app.clone();
+                    let input = usage.input_tokens;
+                    let output = usage.output_tokens;
+                    tauri::async_runtime::spawn(async move {
+                        record_cost(&app_clone, input, output, cost_usd).await;
+                    });
+
                     // Don't emit here - we'll emit on Result message instead
                     // This reduces the frequency of updates
                 } else {
@@ -635,6 +677,7 @@ fn process_json_line(
                                 content: desc,
                                 tool_name: Some(name.clone()),
                                 conversation_id: conversation_id.clone(),
+                                cost: None, // Tool use doesn't have separate cost
                             },
                         );
                     }
@@ -652,6 +695,7 @@ fn process_json_line(
                                 content: text.clone(),
                                 tool_name: None,
                                 conversation_id: conversation_id.clone(),
+                                cost: message_cost.clone(), // Include cost with assistant text
                             },
                         );
                     }
@@ -664,6 +708,7 @@ fn process_json_line(
                                 content: format!("[Thinking] {}", thinking),
                                 tool_name: None,
                                 conversation_id: conversation_id.clone(),
+                                cost: None,
                             },
                         );
                     }
@@ -723,9 +768,20 @@ fn process_json_line(
                     stats_guard.model.clone().unwrap_or_else(|| "claude-opus-4-20250514".to_string())
                 };
 
+                // Calculate cost for historical tracking
+                let cost_usd = calculate_cost(usage_info.input_tokens, usage_info.output_tokens, &model);
+
                 let mut stats_guard = stats.write();
                 stats_guard.add_usage(usage_info.input_tokens, usage_info.output_tokens, &model);
                 println!("Result message tokens - input: {}, output: {}", usage_info.input_tokens, usage_info.output_tokens);
+
+                // Record to historical cost tracking
+                let app_clone = app.clone();
+                let input = usage_info.input_tokens;
+                let output = usage_info.output_tokens;
+                tauri::async_runtime::spawn(async move {
+                    record_cost(&app_clone, input, output, cost_usd).await;
+                });
             }
 
             // Always emit updated stats on result message (less frequent)
@@ -797,6 +853,7 @@ fn process_json_line(
                             content: text.clone(),
                             tool_name: None,
                             conversation_id: conversation_id.clone(),
+                            cost: None,
                         },
                     );
                 }