Welcome box with Recent Activity stops showing after lastReleaseNotesSeen is set

Bug Description

The startup welcome box (containing the Claude logo, "Recent activity", and "What's new" / tips) used to appear on every launch. As of recently, it only appears once per version update and then disappears on subsequent launches.

Steps to Reproduce

1. Launch claude — welcome box appears with Recent Activity and What's New
2. Exit and launch claude again — welcome box is gone, only the bare logo + horizontal separator lines are shown

Expected Behavior

The welcome box with Recent Activity and tips should appear on every startup, as it did previously.

Workaround

Setting lastReleaseNotesSeen in ~/.claude.json to an older version (e.g., "0.0.0") restores the welcome box. However, Claude Code overwrites this value back to the current version after each session.

Environment

• Claude Code v2.1.72 (also tested with v2.1.71 — same behavior)
• macOS (Darwin 25.3.0, Apple Silicon)
• Tested on both Ghostty and Terminal.app — same result
• Claude Pro subscription

Before (expected every launch)

╭─── Claude Code v2.1.72 ─────────────────────────────────────────────╮
│                                │ Recent activity                    │
│          Welcome back!         │ 12s ago  previous session ...      │
│                                │ /resume for more                   │
│             ▗ ▗   ▖ ▖         │ ──────────────────────────────────  │
│               ▘▘ ▝▝           │ What's new                         │
│                                │ Fixed tool search ...              │
│   Opus 4.6 · Claude Pro       │ /release-notes for more            │
╰──────────────────────────────────────────────────────────────────────╯

After (current behavior on 2nd+ launch)

 ▐▛███▜▌   Claude Code v2.1.72
▝▜█████▛▘  Sonnet 4.6 · Claude Pro
  ▘▘ ▝▝    /Users/...

──────────────────────────────────────────────────
❯ 
──────────────────────────────────────────────────

This appears to be gated on lastReleaseNotesSeen in ~/.claude.json matching the current version. Previously the welcome box displayed regardless of this value.