Add manual contact entry on iOS

[torlando-tech]

Summary

• add a native + contact action with QR scanning and manual hash/LXMA entry
• keep hash-only contact creation passive and defer path resolution until send time
• reuse previously heard announce names without overwriting custom nicknames
• sequence duplicate-contact feedback safely after sheet dismissal
• add a visible Paste button beside the manual address field
• preserve Network-tab QR scanning and the macOS clipboard workflow

Verification

• 302 shipping XCTest tests passed with zero failures
• 262 static contract tests passed, with 1 expected skip
• Model B simulator build succeeded
• signed physical iPhone build, codesign verification, install, and launch succeeded
• physical checks confirmed manual entry, duplicate feedback dismissal, announced-name reuse, and Paste button behavior
• exact-head standards and specification reviews reported no findings

Risk and rollback

The change is limited to Contacts UI, contact-name selection, and regression coverage. Hash-only additions do not request paths. Rollback is the normal revert of this PR.

[greptile-apps]

Greptile Summary

The PR adds native QR and manual contact entry while keeping hash-only additions passive until send time.

• Adds validated LXMA/hash parsing and contact persistence with announced-name reuse.
• Adds iOS contact-entry sheets, paste support, and safely sequenced duplicate-contact feedback.
• Prevents cancellation and interactive dismissal while an add operation is active.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
Sources/ColumbaApp/ViewModels/ContactsViewModel.swift	Adds manual-input parsing and passive contact persistence while preserving send-time path resolution.
Sources/ColumbaApp/Views/Contacts/AddContactSheet.swift	Adds manual contact entry and prevents dismissal during active persistence, resolving the previously reported cancellation race.
Sources/ColumbaApp/Views/Contacts/ContactsView.swift	Adds the contact action menu and presents existing-contact feedback only after the owning sheet finishes dismissing.
Tests/ColumbaAppTests/AnnounceClassificationTests.swift	Adds coverage for manual hash/LXMA parsing and announced-name persistence.
Tests/static/test_qr_contact_send_path_contract.py	Extends static contracts for passive hash entry, paste affordance, dismissal protection, and feedback sequencing.

_{Reviews (2): Last reviewed commit: "fix: prevent cancellation during contact..." | Re-trigger Greptile}