fix: buffer split mouse sequences, widen grid buttons, fix [object Object] in tab bar

- Buffer partial escape sequences in stdin handler so split SGR mouse
  events don't leak garbage characters into PTY panes
- Widen pane button hit areas from 1 char to 2-4 chars each; add title
  row click-to-expand; widen tab close/add buttons and pane list targets
- Fix [object Object] rendering in picker tab bar and pane list caused
  by OpenTUI's t`` tag not handling StyledText interpolation; add st()
  helper that concatenates StyledText by merging chunk arrays

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

src/data/session-store.ts

@@ -0,0 +1,119 @@
+import { existsSync, mkdirSync, writeFileSync, unlinkSync } from "fs"
+import { join, dirname } from "path"
+import { app } from "../lib/state"
+import type { SavedSession, SavedTab, SavedPane } from "../lib/types"
+import { createSession } from "../pty/session-manager"
+import { ensureGridView, switchToGridTab } from "../grid/view-switch"
+
+const SESSION_PATH = join(process.env.HOME ?? "", ".config", "cladm", "session.json")
+
+export function extractSessionState(): SavedSession | null {
+  const dg = app.directGrid
+  if (!dg || app.gridTabs.length === 0) return null
+
+  const tabs: SavedTab[] = []
+  for (const tab of app.gridTabs) {
+    const paneInfos = dg.getTabPanes(tab.id)
+    const panes: SavedPane[] = []
+    for (const p of paneInfos) {
+      if (!p.session.alive) continue
+      panes.push({
+        projectPath: p.session.projectPath,
+        projectName: p.session.projectName,
+        sessionId: p.session.sessionId,
+        targetBranch: p.session.targetBranch,
+      })
+    }
+    if (panes.length > 0) {
+      tabs.push({ id: tab.id, name: tab.name, panes })
+    }
+  }
+
+  if (tabs.length === 0) return null
+
+  const activeIdx = app.gridTabs.findIndex(t => t.id === dg.activeTabId)
+  return {
+    version: 1,
+    savedAt: Date.now(),
+    activeTabIndex: Math.max(0, activeIdx),
+    nextTabId: app.nextTabId,
+    tabs,
+  }
+}
+
+export function saveSessionSync(data: SavedSession): void {
+  const dir = dirname(SESSION_PATH)
+  if (!existsSync(dir)) mkdirSync(dir, { recursive: true })
+  writeFileSync(SESSION_PATH, JSON.stringify(data, null, 2))
+}
+
+export async function loadSavedSession(): Promise<SavedSession | null> {
+  try {
+    const file = Bun.file(SESSION_PATH)
+    if (!await file.exists()) return null
+    const data = await file.json() as SavedSession
+    if (data.version !== 1 || !Array.isArray(data.tabs)) return null
+    return data
+  } catch {
+    return null
+  }
+}
+
+export function deleteSavedSession(): void {
+  try { unlinkSync(SESSION_PATH) } catch {}
+}
+
+export async function restoreSession(saved: SavedSession, useResume: boolean): Promise<void> {
+  ensureGridView()
+
+  const termW = process.stdout.columns || 120
+  const termH = process.stdout.rows || 40
+
+  let firstTabId: number | null = null
+
+  for (const savedTab of saved.tabs) {
+    const tabId = app.nextTabId++
+    const tab = { id: tabId, name: savedTab.name }
+    app.gridTabs.push(tab)
+    app.directGrid!.addTab(tab)
+    if (firstTabId === null) firstTabId = tabId
+
+    const validPanes = savedTab.panes.filter(p => existsSync(p.projectPath))
+    const n = validPanes.length
+    const cols = n <= 1 ? 1 : n <= 2 ? 2 : n <= 4 ? 2 : 3
+    const rows = Math.ceil(n / cols)
+    const paneW = Math.max(Math.floor(termW / cols) - 2, 20)
+    const paneH = Math.max(Math.floor((termH - 2) / rows) - 4, 6)
+
+    for (const pane of validPanes) {
+      const session = await createSession({
+        projectPath: pane.projectPath,
+        projectName: pane.projectName,
+        sessionId: useResume ? pane.sessionId : undefined,
+        targetBranch: pane.targetBranch,
+        width: paneW,
+        height: paneH,
+      })
+      await app.directGrid!.addPane(session, tabId)
+    }
+  }
+
+  // Sort tabs by name
+  app.gridTabs.sort((a, b) => {
+    const na = parseInt(a.name.replace(/\D/g, "")) || 0
+    const nb = parseInt(b.name.replace(/\D/g, "")) || 0
+    return na - nb
+  })
+
+  // Switch to saved active tab
+  const targetIdx = Math.min(saved.activeTabIndex, app.gridTabs.length - 1)
+  if (targetIdx >= 0 && app.gridTabs[targetIdx]) {
+    switchToGridTab(app.gridTabs[targetIdx].id)
+  } else if (firstTabId !== null) {
+    switchToGridTab(firstTabId)
+  }
+
+  deleteSavedSession()
+  app.savedSession = null
+  app.restoreMode = null
+}