fix(baileys): show saved/contact names in the Chats list (#369)

[rmyndharis]

Closes #369.

Problem

On the Baileys engine, the dashboard Chats list showed a raw number — or a privacy-id for @lid contacts — instead of the saved/contact name. The dashboard already renders chat.name || chat.id.split('@')[0], so the gap was server-side: BaileysSessionStore.toNeutralChat() returned name: c.name ?? userPart(c.id) and never consulted the synced contacts map, even though the name data (name / verifiedName / notify), the lidToPn map, and resolvePhone() all already live in that same store.

Fix

Add a resolveContactName(id) priority chain used only when Baileys gives the chat no title:

1. Chat title (Chat.name) — unchanged, still wins.
2. Saved contact name → verifiedName → pushName (notify).
3. For a @lid chat: resolve to the phone via lidToPn / contact.phoneNumber, then look up that phone-JID contact's name.
4. Raw user-part — last resort (previous behavior), so a number/lid is never shown as a JID.

Engine-neutral: no interface change — ChatSummary.name is simply better populated. whatsapp-web.js is unaffected.

Tests

Added 5 cases to baileys-session-store.spec.ts (TDD, watched them fail first): chat-title-wins, contact-name fallthrough, @lid via lidToPn, pushName fallback, raw-user-part last resort.

• npx jest → 933/933 pass (86 suites)
• npm run build clean, eslint clean

Notes

• Builds on the identity work merged in feat(engine): engine-neutral WhatsApp identities (Baileys inbound conformance) #342.
• pushName is the sender's self-chosen name, not the address-book label — it's the documented last-name-source before the raw id, so a displayed name may differ from a phone's contact label for hidden-number contacts (inherent Baileys limitation).