Fix contact lookup for WhatsApp LID (Linked Device ID) migration

[coucaj]

Problem

WhatsApp migrated contacts from phone-based JIDs (155...@s.whatsapp.net) to internal LID JIDs (123...@lid) for privacy. This broke several functions in whatsapp.py:

• search_contacts("Name") returned nothing even if the contact existed
• get_direct_chat_by_contact(phone) returned None
• list_messages(sender_phone_number=phone) returned an empty list
• Contact names showed as raw numeric IDs

The root cause: whatsapp.py only used messages.db for contact lookup, but messages.db stores chats by LID and does not have real names for those contacts. The real mapping lives in whatsapp.db (written by the Go bridge).

Solution

Add three helpers and patch four functions to use the LID -> phone mapping from whatsapp.db.

New helpers

• _normalize_phone(phone) — strips +, spaces, dashes
• _resolve_phone_to_jids(phone) — queries whatsmeow_lid_map to return all JID variants for a phone number; uses suffix match (last 10 digits) to handle number format differences (e.g. 15550001234 vs 115550001234)
• _get_contact_name(phone) — looks up full_name / push_name in whatsmeow_contacts

Fixed functions

Function	Change
search_contacts	Query whatsapp.db first (real names + LID support), fall back to messages.db
get_direct_chat_by_contact	Use _resolve_phone_to_jids and resolve name from store
list_messages	Filter by all JID variants when sender_phone_number is provided
list_messages	Skip include_context expansion when filtering by phone (prevents duplicate messages)

Testing

Tested with an account where multiple contacts had migrated to LID JIDs. After the patch:

search_contacts("John")                        # Returns contact with real name
get_direct_chat_by_contact("+1 555 000 1234")  # Returns chat by phone number
list_messages(sender_phone_number="1555...")   # Returns clean conversation, no duplicates

Notes

• No breaking changes — all existing function signatures are preserved
• whatsapp.db path is derived relative to the script location (same pattern as messages.db)
• Suffix matching handles the common case where WhatsApp stores numbers with/without country code prefix digits