Complete modern webinterface implementation with comprehensive grid features and help system#7

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mastertvheadend/tvheadend-test:masterfrom

copilot/fix-f55820a4-ee25-49e1-bc16-d120bd11368ftvheadend/tvheadend-test:copilot/fix-f55820a4-ee25-49e1-bc16-d120bd11368fCopy head branch name to clipboard