fix: preserve sent message text below reply preview

[torlando-tech]

Summary

• prevent the reply-preview accent bar from expanding to the parent height
• preserve the full wrapped message body while retaining the two-line reply preview
• add a native SwiftUI geometry regression and retained visual artifact

Verification

• regression before fix: 1 test executed, 1 failed with a 1000-point fitted height
• focused regression after fix: 1 test executed, 1 passed
• full shipping ColumbaAppTests: 162 tests passed
• simulator-rendered bubble visually verified with complete body text and correctly sized accent bar
• two independent exact-head reviews approved commit 013dce0e1bbac86f8ffd9277e13a699029081bea

Risk and rollback

• low-risk localized SwiftUI layout change
• rollback by reverting the three commits in this PR

[greptile-apps]

Greptile Summary

The PR adjusts the SwiftUI reply-preview and message-body sizing behavior and adds a native layout regression test.

• Renders the reply accent bar as an overlay sized to the preview.
• Gives the reply preview and message body their intrinsic wrapped height.
• Adds the layout test to the shipping app test target and retains a rendered artifact.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
Sources/ColumbaApp/Views/Messaging/MessageBubble.swift	Reworks the reply preview accent bar as an overlay and preserves intrinsic vertical sizing for wrapped preview and body text.
Tests/ColumbaAppTests/MessageBubbleLayoutTests.swift	Adds fitted-height coverage and a retained rendered artifact for a sent reply bubble with a long message body.
Columba.xcodeproj/project.pbxproj	Registers MessageBubbleLayoutTests.swift with the ColumbaAppTests group and sources build phase.

_{Reviews (2): Last reviewed commit: "test: assert reply bubbles preserve full..." | Re-trigger Greptile}