feat: project context panel for persistent PROJECT/REQUIREMENTS/ROADMAP/STATE files (#188)

- Add projectContext store with load/save via existing Tauri file commands
- Add ProjectContextPanel modal with tabbed editor, file-exists badges, and templates
- Add injectTextStore signal so StatusBar can inject content directly into InputBar
- Add PROJECT_CONTEXT_SYSTEM_ADDENDUM auto-appended to custom_instructions on connect
- Add open-book button to StatusBar to open the panel
- Add PROJECT.md example file for the hikari-desktop project itself
- 34 tests covering all store methods, exports, and signal behaviour

src/lib/components/StatusBar.svelte

@@ -30,6 +30,8 @@
   import CastPanel from "./CastPanel.svelte";
   import PluginManagementPanel from "./PluginManagementPanel.svelte";
   import McpManagementPanel from "./McpManagementPanel.svelte";
+  import ProjectContextPanel from "./ProjectContextPanel.svelte";
+  import { injectTextStore, PROJECT_CONTEXT_SYSTEM_ADDENDUM } from "$lib/stores/projectContext";
   import { conversationsStore } from "$lib/stores/conversations";
   import {
     generateContextInjection,
@@ -62,6 +64,7 @@
   let showCastPanel = $state(false);
   let showPluginPanel = $state(false);
   let showMcpPanel = $state(false);
+  let showProjectContext = $state(false);
   let isSummarising = $state(false);
   let showWorkspaceTrust = $state(false);
   let pendingHookInfo: WorkspaceHookInfo | null = $state(null);
@@ -185,7 +188,8 @@
           working_dir: targetDir,
           model: currentConfig.model || null,
           api_key: currentConfig.api_key || null,
-          custom_instructions: currentConfig.custom_instructions || null,
+          custom_instructions:
+            (currentConfig.custom_instructions ?? "") + PROJECT_CONTEXT_SYSTEM_ADDENDUM,
           mcp_servers_json: currentConfig.mcp_servers_json || null,
           allowed_tools: allAllowedTools,
           use_worktree: currentConfig.use_worktree ?? false,
@@ -300,6 +304,10 @@
     onToggleAchievements();
   }
 
+  function handleInjectContext(content: string): void {
+    injectTextStore.set(content);
+  }
+
   async function handleCompactConversation() {
     const activeId = get(conversationsStore.activeConversationId);
     if (!activeId) return;
@@ -345,7 +353,8 @@
           working_dir: workingDirectory || selectedDirectory,
           model: currentConfig.model || null,
           api_key: currentConfig.api_key || null,
-          custom_instructions: currentConfig.custom_instructions || null,
+          custom_instructions:
+            (currentConfig.custom_instructions ?? "") + PROJECT_CONTEXT_SYSTEM_ADDENDUM,
           mcp_servers_json: currentConfig.mcp_servers_json || null,
           allowed_tools: allAllowedTools,
           use_worktree: currentConfig.use_worktree ?? false,
@@ -564,6 +573,20 @@
         />
       </svg>
     </button>
+    <button
+      onclick={() => (showProjectContext = true)}
+      class="p-1 text-gray-500 icon-trans-hover"
+      title="Project Context"
+    >
+      <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path
+          stroke-linecap="round"
+          stroke-linejoin="round"
+          stroke-width="2"
+          d="M12 6.253v13m0-13C10.832 5.477 9.246 5 7.5 5S4.168 5.477 3 6.253v13C4.168 18.477 5.754 18 7.5 18s3.332.477 4.5 1.253m0-13C13.168 5.477 14.754 5 16.5 5c1.747 0 3.332.477 4.5 1.253v13C19.832 18.477 18.247 18 16.5 18c-1.746 0-3.332.477-4.5 1.253"
+        />
+      </svg>
+    </button>
     <button
       onclick={toggleEditor}
       disabled={connectionStatus !== "connected"}
@@ -827,6 +850,14 @@
   <McpManagementPanel onClose={() => (showMcpPanel = false)} />
 {/if}
 
+{#if showProjectContext}
+  <ProjectContextPanel
+    onClose={() => (showProjectContext = false)}
+    onInject={handleInjectContext}
+    workingDirectory={workingDirectory || selectedDirectory}
+  />
+{/if}
+
 {#if showWorkspaceTrust && pendingHookInfo}
   <WorkspaceTrustModal
     hookInfo={pendingHookInfo}