feat: batch of fixes and features (#56)

## Summary

This PR includes a batch of bug fixes and new features:

### Bug Fixes
- **Links in chat history now open in default browser** instead of navigating within the app
  - Closes #54
- **Allow spaces in tab names** - space key no longer acts like enter when renaming tabs
  - Closes #52

### New Features
- **`/cd` command** - Change the working directory of an active tab with context preservation
  - Closes #55
- **`/search` command** - Search and highlight matches within the conversation
  - Closes #32

## Test Plan
- [ ] Click a link in chat history and verify it opens in the default browser
- [ ] Rename a tab and verify spaces can be typed
- [ ] Use `/cd <path>` and verify the directory changes while preserving conversation context
- [ ] Use `/search <query>` and verify matches are highlighted in yellow
- [ ] Use `/search` with no args to clear the search highlighting

✨ This PR was created with help from Hikari~ 🌸

Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Reviewed-on: #56
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

src/lib/components/Terminal.svelte

@@ -3,10 +3,17 @@
   import { afterUpdate } from "svelte";
   import ConversationTabs from "./ConversationTabs.svelte";
   import Markdown from "./Markdown.svelte";
+  import HighlightedText from "./HighlightedText.svelte";
+  import { searchState, searchQuery } from "$lib/stores/search";
 
   let terminalElement: HTMLDivElement;
   let shouldAutoScroll = true;
   let lines: TerminalLine[] = [];
+  let currentSearchQuery = "";
+
+  searchQuery.subscribe((value) => {
+    currentSearchQuery = value;
+  });
 
   claudeStore.terminalLines.subscribe((value) => {
     lines = value;
@@ -64,6 +71,23 @@
       minute: "2-digit",
     });
   }
+
+  $: {
+    if (currentSearchQuery && lines.length > 0) {
+      const escapedQuery = currentSearchQuery.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+      const regex = new RegExp(escapedQuery, "gi");
+      let totalMatches = 0;
+      for (const line of lines) {
+        const matches = line.content.match(regex);
+        if (matches) {
+          totalMatches += matches.length;
+        }
+      }
+      searchState.setMatchCount(totalMatches);
+    } else {
+      searchState.setMatchCount(0);
+    }
+  }
 </script>
 
 <div
@@ -102,9 +126,9 @@
             <span class="terminal-tool-name mr-2">[{line.toolName}]</span>
           {/if}
           {#if line.type === "assistant"}
-            <Markdown content={line.content} />
+            <Markdown content={line.content} searchQuery={currentSearchQuery} />
           {:else}
-            <span class="whitespace-pre-wrap">{line.content}</span>
+            <HighlightedText content={line.content} searchQuery={currentSearchQuery} />
           {/if}
         </div>
       {/each}
@@ -162,4 +186,11 @@
   .terminal-header-text {
     color: var(--text-secondary);
   }
+
+  :global(.search-highlight) {
+    background-color: var(--search-highlight, #fbbf24);
+    color: var(--search-highlight-text, #000);
+    border-radius: 2px;
+    padding: 0 2px;
+  }
 </style>