feat: add multiple productivity features and UI enhancements (#68)

## Summary

This PR adds a collection of productivity features and UI enhancements to improve the Hikari Desktop experience:

### New Features
- **Clipboard History** (#25) - Track and manage copied code snippets with language detection, search, filtering, and pinning
- **Quick Actions Panel** (#15) - Buttons for common quick actions like "Review PR", "Run tests", "Explain file", with customizable actions
- **Git Integration Panel** (#24) - View current branch, changed/staged files, quick git actions (commit, push, pull), and branch management
- **Session Import/Export** (#8) - Export conversations to JSON and import previously saved sessions
- **Snippet Library** (#22) - Save and reuse common prompts with categories and quick insert
- **Session History** (#14) - Auto-save conversations with browsable history and search
- **High Contrast Mode** (#20) - Accessibility theme with improved visibility
- **Minimize to System Tray** (#11) - System tray support with right-click menu

### UI Enhancements
- Trans-pride gradient theme applied across UI elements
- Copy button added to code blocks
- Linter formatting and eslint-disable comments for cleaner code

## Closes

Closes #8
Closes #11
Closes #14
Closes #15
Closes #20
Closes #22
Closes #24
Closes #25
Closes #34
Closes #35
Closes #36
Closes #37
Closes #69
Closes #70

## Test Plan

- [ ] Verify clipboard history captures code from code block copy buttons
- [ ] Verify clipboard history captures manually selected text from terminal
- [ ] Test snippet library CRUD operations and insertion
- [ ] Test quick actions panel with default and custom actions
- [ ] Test git panel shows correct status, branch, and performs git operations
- [ ] Test session history auto-save and restore
- [ ] Test session import/export roundtrip
- [ ] Verify high contrast mode provides adequate contrast
- [ ] Test minimize to tray functionality and tray menu
- [ ] Verify trans-pride gradient theme displays correctly in all themes

---
*✨ This PR was created with help from Hikari~ 🌸*

Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Reviewed-on: #68
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

src-tauri/src/stats.rs

@@ -1,7 +1,9 @@
 use crate::achievements::{check_achievements, AchievementProgress};
+use chrono::{Local, Timelike};
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 use std::time::Instant;
+use tauri_plugin_store::StoreExt;
 
 #[derive(Debug, Clone, Serialize, Deserialize, Default)]
 pub struct UsageStats {
@@ -28,6 +30,14 @@ pub struct UsageStats {
     #[serde(skip)]
     pub session_start: Option<Instant>,
 
+    // Extended tracking for achievements
+    pub sessions_started: u64,
+    pub consecutive_days: u64,
+    pub total_days_used: u64,
+    pub morning_sessions: u64, // Sessions started before 9 AM
+    pub night_sessions: u64,   // Sessions started after 10 PM
+    pub last_session_date: Option<String>, // ISO date string for streak tracking
+
     // Achievement tracking
     #[serde(skip)]
     pub achievements: AchievementProgress,
@@ -65,6 +75,47 @@ impl UsageStats {
         self.session_duration_seconds = 0;
         self.session_start = Some(Instant::now());
         self.achievements.start_session();
+
+        // Track session start for achievements
+        self.track_session_start();
+    }
+
+    pub fn track_session_start(&mut self) {
+        let now = Local::now();
+        let today = now.format("%Y-%m-%d").to_string();
+        let hour = now.hour();
+
+        // Increment session count
+        self.sessions_started += 1;
+
+        // Track morning/night sessions
+        if hour < 9 {
+            self.morning_sessions += 1;
+        }
+        if hour >= 22 {
+            self.night_sessions += 1;
+        }
+
+        // Track consecutive days and total days
+        if let Some(last_date) = &self.last_session_date {
+            if last_date != &today {
+                // Check if it's the next day (consecutive)
+                if is_consecutive_day(last_date, &today) {
+                    self.consecutive_days += 1;
+                } else {
+                    // Streak broken
+                    self.consecutive_days = 1;
+                }
+                self.total_days_used += 1;
+                self.last_session_date = Some(today);
+            }
+            // Same day - don't increment anything
+        } else {
+            // First session ever
+            self.consecutive_days = 1;
+            self.total_days_used = 1;
+            self.last_session_date = Some(today);
+        }
     }
 
     pub fn increment_messages(&mut self) {
@@ -127,12 +178,34 @@ impl UsageStats {
             session_tools_usage: self.session_tools_usage.clone(),
             session_duration_seconds: self.session_duration_seconds,
             session_start: self.session_start,
+            sessions_started: self.sessions_started,
+            consecutive_days: self.consecutive_days,
+            total_days_used: self.total_days_used,
+            morning_sessions: self.morning_sessions,
+            night_sessions: self.night_sessions,
+            last_session_date: self.last_session_date.clone(),
             achievements: AchievementProgress::new(), // Dummy for copy
         };
         check_achievements(&stats_copy, &mut self.achievements)
     }
 }
 
+// Helper function to check if two dates are consecutive
+fn is_consecutive_day(prev_date: &str, current_date: &str) -> bool {
+    use chrono::NaiveDate;
+
+    let prev = NaiveDate::parse_from_str(prev_date, "%Y-%m-%d").ok();
+    let current = NaiveDate::parse_from_str(current_date, "%Y-%m-%d").ok();
+
+    match (prev, current) {
+        (Some(p), Some(c)) => {
+            let diff = c.signed_duration_since(p).num_days();
+            diff == 1
+        }
+        _ => false,
+    }
+}
+
 // Pricing as of January 2025
 // https://www.anthropic.com/pricing
 fn calculate_cost(input_tokens: u64, output_tokens: u64, model: &str) -> f64 {
@@ -169,6 +242,111 @@ pub struct StatsUpdateEvent {
     pub stats: UsageStats,
 }
 
+/// Serializable struct for persisting only lifetime (total) stats
+#[derive(Debug, Clone, Serialize, Deserialize, Default)]
+pub struct PersistedStats {
+    pub total_input_tokens: u64,
+    pub total_output_tokens: u64,
+    pub total_cost_usd: f64,
+    pub messages_exchanged: u64,
+    pub code_blocks_generated: u64,
+    pub files_edited: u64,
+    pub files_created: u64,
+    pub tools_usage: HashMap<String, u64>,
+    pub sessions_started: u64,
+    pub consecutive_days: u64,
+    pub total_days_used: u64,
+    pub morning_sessions: u64,
+    pub night_sessions: u64,
+    pub last_session_date: Option<String>,
+}
+
+impl From<&UsageStats> for PersistedStats {
+    fn from(stats: &UsageStats) -> Self {
+        PersistedStats {
+            total_input_tokens: stats.total_input_tokens,
+            total_output_tokens: stats.total_output_tokens,
+            total_cost_usd: stats.total_cost_usd,
+            messages_exchanged: stats.messages_exchanged,
+            code_blocks_generated: stats.code_blocks_generated,
+            files_edited: stats.files_edited,
+            files_created: stats.files_created,
+            tools_usage: stats.tools_usage.clone(),
+            sessions_started: stats.sessions_started,
+            consecutive_days: stats.consecutive_days,
+            total_days_used: stats.total_days_used,
+            morning_sessions: stats.morning_sessions,
+            night_sessions: stats.night_sessions,
+            last_session_date: stats.last_session_date.clone(),
+        }
+    }
+}
+
+impl UsageStats {
+    /// Apply persisted stats to restore lifetime totals
+    pub fn apply_persisted(&mut self, persisted: PersistedStats) {
+        self.total_input_tokens = persisted.total_input_tokens;
+        self.total_output_tokens = persisted.total_output_tokens;
+        self.total_cost_usd = persisted.total_cost_usd;
+        self.messages_exchanged = persisted.messages_exchanged;
+        self.code_blocks_generated = persisted.code_blocks_generated;
+        self.files_edited = persisted.files_edited;
+        self.files_created = persisted.files_created;
+        self.tools_usage = persisted.tools_usage;
+        self.sessions_started = persisted.sessions_started;
+        self.consecutive_days = persisted.consecutive_days;
+        self.total_days_used = persisted.total_days_used;
+        self.morning_sessions = persisted.morning_sessions;
+        self.night_sessions = persisted.night_sessions;
+        self.last_session_date = persisted.last_session_date;
+    }
+}
+
+/// Save lifetime stats to persistent store
+pub async fn save_stats(app: &tauri::AppHandle, stats: &UsageStats) -> Result<(), String> {
+    let store = app.store("stats.json").map_err(|e| e.to_string())?;
+
+    let persisted = PersistedStats::from(stats);
+
+    println!("Saving stats: {:?}", persisted);
+
+    store.set(
+        "lifetime_stats",
+        serde_json::to_value(persisted).map_err(|e| e.to_string())?,
+    );
+    store.save().map_err(|e| e.to_string())?;
+
+    println!("Stats saved successfully");
+    Ok(())
+}
+
+/// Load lifetime stats from persistent store
+pub async fn load_stats(app: &tauri::AppHandle) -> Option<PersistedStats> {
+    println!("Loading stats from store...");
+
+    let store = match app.store("stats.json") {
+        Ok(s) => s,
+        Err(e) => {
+            println!("Failed to open stats store: {}", e);
+            return None;
+        }
+    };
+
+    if let Some(stats_value) = store.get("lifetime_stats") {
+        println!("Found lifetime stats in store: {:?}", stats_value);
+        if let Ok(persisted) = serde_json::from_value::<PersistedStats>(stats_value.clone()) {
+            println!("Loaded lifetime stats successfully");
+            return Some(persisted);
+        } else {
+            println!("Failed to parse lifetime stats");
+        }
+    } else {
+        println!("No lifetime stats found in store");
+    }
+
+    None
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;