Bring Phase 4 furniture and lighting to Forge 26.3

[SkyBlade1978]

What changes

Adds Phase 4 to Forge 26.3: wingback chairs, thrones, wooden and canopy beds, doubles, and separate Chairs, Benches, Beds and Lights tabs.

Shield chairs keep the original shield, including its damage, name and banner design. Empty chairs show the open wooden frame. Candle sconces hold up to four vanilla candles in mixed colours, with safe removal and recovery of the original items.

The lighting changes include the recent hand-mining, support-loss, waterlogging, redstone, bucket and lava-lamp fixes. Sconce metals have separate block identities without changing existing frame item IDs; older worlds retain their furniture and saved metal types.

Biomes O' Plenty furniture remains in the separate add-on. This build is for Forge, not NeoForge.

Checked

• Local build, Javadoc, catalog, resource, locale, metadata, hygiene, artifact and Eclipse checks.
• Packaged clients and servers on Forge 66.0.2 and 66.0.13, including stable/newer BOP, disabled features and multiplayer candle/shield synchronisation.
• First and second loads of 17 copied legacy fixtures; original worlds were not changed.
• Matching main, sources and Javadoc hashes across two clean builds.
• Manual testing completed by John, including the recent Eclipse fixes.

README, changelog and upgrade guidance describe the player-facing behaviour and migration limits. Local settings, worlds, logs and agent files are excluded.