Wrap electronic pickles cover titles

[walker1211]

Summary

• Split electronic pickles manifest cover titles at the column/date separator for a cleaner two-line cover layout.
• Add a regression test for card manifest deck generation.

Test plan

• go test ./internal/app -run 'Test(BuildCardManifestDeckWrapsElectronicPicklesCoverTitle|ServiceGeneratePreviewBuildsCardManifest|ServiceGeneratePreviewFitsCardManifest|ServiceGeneratePreviewReturnsErrorForUnknownCardManifestSectionField|ServiceGeneratePreviewBuildsNoImageCardManifestItemsAsTextCaption|ServiceGeneratePreviewBuildsCardManifestDeckWithoutAI)'
• go test ./...
• go build -o ./mark2note ./cmd/mark2note