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/lib/components/Terminal.svelte

@@ -1,10 +1,12 @@
 <script lang="ts">
   import { claudeStore, type TerminalLine } from "$lib/stores/claude";
-  import { afterUpdate, tick } from "svelte";
+  import { afterUpdate, tick, onMount, onDestroy } from "svelte";
   import ConversationTabs from "./ConversationTabs.svelte";
   import Markdown from "./Markdown.svelte";
   import HighlightedText from "./HighlightedText.svelte";
   import { searchState, searchQuery } from "$lib/stores/search";
+  import { clipboardStore } from "$lib/stores/clipboard";
+  import { shouldHidePaths, maskPaths } from "$lib/stores/config";
 
   let terminalElement: HTMLDivElement;
   let shouldAutoScroll = true;
@@ -17,6 +19,11 @@
     currentSearchQuery = value;
   });
 
+  let hidePaths = false;
+  shouldHidePaths.subscribe((value) => {
+    hidePaths = value;
+  });
+
   claudeStore.terminalLines.subscribe((value) => {
     lines = value;
   });
@@ -122,6 +129,32 @@
       searchState.setMatchCount(0);
     }
   }
+
+  // Handle manual text selection copy events
+  function handleCopy() {
+    const selection = window.getSelection();
+    const selectedText = selection?.toString();
+
+    if (selectedText && selectedText.trim().length > 0) {
+      // Only capture multi-line or longer text (likely code/meaningful content)
+      if (selectedText.includes("\n") || selectedText.length > 50) {
+        clipboardStore.captureClipboard(selectedText, null, "Copied from chat");
+      }
+    }
+  }
+
+  onMount(() => {
+    // Listen for copy events on the terminal
+    if (terminalElement) {
+      terminalElement.addEventListener("copy", handleCopy);
+    }
+  });
+
+  onDestroy(() => {
+    if (terminalElement) {
+      terminalElement.removeEventListener("copy", handleCopy);
+    }
+  });
 </script>
 
 <div
@@ -161,9 +194,15 @@
             <span class="terminal-tool-name mr-2">[{line.toolName}]</span>
           {/if}
           {#if line.type === "assistant"}
-            <Markdown content={line.content} searchQuery={currentSearchQuery} />
+            <Markdown
+              content={maskPaths(line.content, hidePaths)}
+              searchQuery={currentSearchQuery}
+            />
           {:else}
-            <HighlightedText content={line.content} searchQuery={currentSearchQuery} />
+            <HighlightedText
+              content={maskPaths(line.content, hidePaths)}
+              searchQuery={currentSearchQuery}
+            />
           {/if}
         </div>
       {/each}