Fix #271: Add "service update paused" case for swarm deployment log parsing

[Copilot]

Ports yiisoft/app#456. Docker Swarm can fail a deployment with a service update paused state rather than an explicit rollback, which was previously undetected as a failure.

Changes

• Makefile: Extend prod-deploy failure detection grep pattern to include service update paused alongside existing rollback: and update rolled back patterns
• Makefile: Generalize failure error messages from rollback-specific wording to "Docker Swarm update failed" to cover all failure modes
• CHANGELOG.md: Add entry under 1.2.1 under development

# Before
if grep -qiE 'rollback:|update rolled back' deploy.log; then

# After
if grep -qiE 'rollback:|update rolled back|service update paused' deploy.log; then

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