Add onboarding screen for first-time users

- Show welcome view when no project is selected
- Explain the Research → Plan → Implement workflow
- Include ANTHROPIC_API_KEY setup instructions
- List getting started steps (add project, create session, describe work)
- Explain iteration workflow with Review/Submit buttons
- Add CSS styling for onboarding content

1 files changed, 56 insertions, 0 deletions

diff --git a/renderer/src/styles/globals.css b/renderer/src/styles/globals.css
index d917f7e..809ff15 100644
--- a/renderer/src/styles/globals.css
+++ b/renderer/src/styles/globals.css
@@ -413,3 +413,59 @@ body {
 .error-bar button:hover {
   opacity: 0.8;
 }
+
+/* Onboarding */
+.onboarding h1 {
+  font-size: 32px;
+  margin-bottom: 8px;
+}
+
+.onboarding h2 {
+  font-size: 20px;
+  margin-top: 28px;
+  margin-bottom: 12px;
+  color: var(--accent);
+}
+
+.onboarding p {
+  margin: 12px 0;
+  line-height: 1.6;
+}
+
+.onboarding ol {
+  margin: 12px 0 12px 24px;
+}
+
+.onboarding li {
+  margin: 8px 0;
+  line-height: 1.5;
+}
+
+.onboarding pre {
+  background: var(--bg-tertiary);
+  padding: 12px 16px;
+  border-radius: 6px;
+  margin: 12px 0;
+}
+
+.onboarding code {
+  font-family: "SF Mono", Monaco, monospace;
+  font-size: 13px;
+}
+
+.onboarding a {
+  color: var(--accent);
+  text-decoration: none;
+}
+
+.onboarding a:hover {
+  text-decoration: underline;
+}
+
+.onboarding-tip {
+  margin-top: 28px;
+  padding: 16px;
+  background: var(--bg-tertiary);
+  border-left: 3px solid var(--accent);
+  border-radius: 0 6px 6px 0;
+}