refactor: extract index.ts into 7 focused modules

Break 1507-line index.ts into a slim 251-line entry point plus:
- lib/theme.ts, lib/state.ts (shared constants + app singleton)
- ui/formatters.ts, ui/panels.ts (row formatting + UI updates)
- input/parser.ts, input/handlers.ts (stdin parsing + keyboard/mouse)
- grid/view-switch.ts, actions/launch.ts (grid switching + PTY launch)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/actions/launch.ts

@@ -0,0 +1,71 @@
+import { app } from "../lib/state"
+import { updateAll, rebuildDisplayRows } from "../ui/panels"
+import { ensureGridView } from "../grid/view-switch"
+import { loadSessions } from "../data/sessions"
+import { createSession } from "../pty/session-manager"
+
+export async function doLaunch() {
+  if (app.selectedProjects.size === 0 && app.selectedSessions.size === 0) return
+  if (app.demoMode) {
+    app.selectedProjects.clear()
+    app.selectedSessions.clear()
+    app.selectedBranches.clear()
+    rebuildDisplayRows()
+    updateAll()
+    return
+  }
+
+  const items: { path: string; name: string; sessionId?: string; targetBranch?: string }[] = []
+
+  for (const path of app.selectedProjects) {
+    const project = app.projects.find(p => p.path === path)
+    if (!project) continue
+    const targetBranch = app.selectedBranches.get(path)
+    const needsBranch = targetBranch && targetBranch !== project.branch
+    if (!project.sessions) {
+      project.sessions = await loadSessions(project.path)
+      project.sessionCount = project.sessions.length
+    }
+    const lastSessionId = project.sessions[0]?.id
+    items.push({ path, name: project.name, sessionId: lastSessionId, targetBranch: needsBranch ? targetBranch : undefined })
+  }
+
+  for (const project of app.projects) {
+    if (!project.sessions) continue
+    for (const session of project.sessions) {
+      if (app.selectedSessions.has(session.id)) {
+        const targetBranch = app.selectedBranches.get(project.path)
+        const needsBranch = targetBranch && targetBranch !== project.branch
+        items.push({ path: project.path, name: project.name, sessionId: session.id, targetBranch: needsBranch ? targetBranch : undefined })
+      }
+    }
+  }
+
+  if (items.length === 0) return
+
+  ensureGridView()
+
+  const termW = process.stdout.columns || 120
+  const termH = process.stdout.rows || 40
+  const totalPanes = items.length + (app.directGrid?.paneCount || 0)
+  const cols = totalPanes <= 1 ? 1 : totalPanes <= 2 ? 2 : totalPanes <= 4 ? 2 : 3
+  const rows = Math.ceil(totalPanes / cols)
+  const paneW = Math.max(Math.floor(termW / cols) - 2, 20)
+  const paneH = Math.max(Math.floor((termH - 2) / rows) - 4, 6)
+
+  for (const item of items) {
+    const session = await createSession({
+      projectPath: item.path,
+      projectName: item.name,
+      sessionId: item.sessionId,
+      targetBranch: item.targetBranch,
+      width: paneW,
+      height: paneH,
+    })
+    await app.directGrid!.addPane(session)
+  }
+
+  app.selectedProjects.clear()
+  app.selectedSessions.clear()
+  app.selectedBranches.clear()
+}