feat: resolve contact names for chat and message display

[jsindy]

Problem

Phone numbers and emails in chat listings, message history, and watch streams are displayed as raw handles (+14155551212) with no way to identify who they belong to. The chats command's display_name field is usually empty for 1:1 conversations since Messages.app doesn't populate it. There's also no way to send a message by contact name — --to requires a phone number or email.

Solution

Add macOS Contacts framework integration that resolves handles to display names from the system address book.

New: ContactResolver in IMsgCore

• Preloads all contacts into phone→name and email→name dictionaries on init (~10-50ms for typical address books)
• O(1) lookups via E.164-normalized phone numbers and lowercased emails
• ContactResolving protocol with NoOpContactResolver fallback when Contacts access is denied
• Uses existing PhoneNumberNormalizer for consistent phone normalization

Enriched output across all surfaces

Surface	Before	After
imsg chats	[1] (+14155551212)	[1] John Smith (+14155551212)
imsg history	[recv] +14155551212: hello	[recv] John Smith: hello
imsg watch	[recv] +14155551212: hello	[recv] John Smith: hello
JSON output	"sender": "+14155551212"	"sender": "+14155551212", "sender_name": "John Smith"
RPC chats	no contact info	"contact_name": "John Smith" for 1:1 chats

Send by contact name

imsg send --to "John Smith" --text "hey"
# Resolves to +14155551212 and sends

imsg send --to "John" --text "hey"
# Error if multiple contacts match:
#   Multiple contacts match "John":
#     John Smith: +14155551212
#     John Doe: +15559876543
#   Specify a phone number or email instead.

The resolver is only created when --to looks like a name (not phone/email), so --chat-id sends skip Contacts entirely.

Changes

File	Change
Sources/IMsgCore/ContactResolver.swift	New — protocol, resolver, no-op fallback
Package.swift	Link Contacts framework
Sources/imsg/Resources/Info.plist	Add NSContactsUsageDescription
Resources/imsg.entitlements	Add addressbook entitlement
Sources/imsg/OutputModels.swift	Add optional sender_name / contact_name fields
Sources/imsg/RPCPayloads.swift	Thread contact names through RPC payloads
Sources/imsg/RPCServer.swift	Add contactResolver property
Sources/imsg/RPCServer+Handlers.swift	Resolve names in all handlers
Sources/imsg/ChatTargetResolver.swift	Add looksLikeName + resolveRecipientName
Sources/imsg/Commands/ChatsCommand.swift	Enrich 1:1 chat names
Sources/imsg/Commands/HistoryCommand.swift	Resolve sender names
Sources/imsg/Commands/WatchCommand.swift	Resolve sender names in stream
Sources/imsg/Commands/SendCommand.swift	Support --to "Name"
Sources/imsg/Commands/RpcCommand.swift	Create resolver at server startup
Tests/	New tests for resolver, mock, name resolution, payloads

Caveats

• Requires Contacts permission — macOS will prompt on first use
• If denied, falls back silently to raw handles (no behavior change)
• First run has ~10-50ms overhead to preload contacts; subsequent lookups are O(1)
• --to "Name" requires an unambiguous match; multiple matches produce an error with candidates listed

Testing

• swift build passes cleanly
• Manual testing with 520 real contacts on macOS 15
• Contact names resolve correctly for 1:1 chats in chats, history, watch
• JSON output includes sender_name and contact_name fields
• --to "Name" resolves and sends correctly
• Permission denial gracefully falls back to raw handles

[barronlroth]

We need this! LGTM.

[steipete]

Thanks @jsindy. I landed a combined maintainer version on main in 5203f74.

I kept the core shape from this PR: optional Contacts lookup, additive JSON/RPC fields (contact_name, sender_name, reaction sender_name), plain-output contact labels, and unambiguous send-by-contact-name. I also rebased it onto the current command/RPC surface, kept raw chat identifiers visible in chats output, added docs/changelog/entitlement updates, and injected a mock resolver in tests so the suite does not prompt for real Contacts.

Proof: local make lint, make build, make test, git diff --check; GitHub CI is green on 5203f74 (run 25308475901). Added co-author credit in the landed commit and changelog. Closing this PR as superseded by main.