fix(maps): restore held and framed map rendering

[AlexProgrammerDE]

Summary

Restore filled maps in the hand and in item frames. Translate current Bedrock map packets in the regular protocol path, keep map IDs stable across item and pixel updates, and send Java frame entities the item and rotation stored in Bedrock block entities. Handle clicks on those synthetic entities without disconnecting.

Why the unusual changes are needed

• Map ID replacement: Bedrock map UUIDs are 64-bit values, while Java's map component and map update packet use an integer ID. A per-connection table gives the item and its later pixel packets the same Java ID. When a filled map first appears, the proxy sends MAP_INFO_REQUEST with a zero client-pixel count. Zero means it has no map pixels yet, so the server sends the image.
• Packet field decoding: Bedrock 1.26.51 encodes each optional map field with its own presence byte. Reading the old update mask left tens of thousands of pixel bytes unread, causing blank maps and disconnects. Tracked actors and decorations have separate presence fields. Tracked actor data is consumed, while the separate decoration list becomes Java map markers. Pixel dimensions and offsets are checked against the 128 by 128 map before allocation and forwarding.
• Colors and transparency: The map pixel integer contains RGBA bytes in little-endian order. Reading it as ARGB swapped red and blue and produced the teal terrain seen during live testing. Fully transparent pixels become Java's empty map color. Opaque colors are matched to the nearest available Java map palette color in Lab space because Java cannot display arbitrary Bedrock RGB values. The match cache now uses the full RGB value: two nearby colors can require different Java palette entries even when they share a coarse color bucket. This removes an avoidable color error, but the fixed Java palette still means a perfect Bedrock pixel match is impossible.
• Frame spawn position and facing: A Bedrock frame is a block; Java renders it as an entity. The Java entity is spawned at the center of the Bedrock block (+0.5 on each coordinate), with Bedrock's facing value in the entity data. The prior corner position misaligned the visible frame. The frame item and rotation come from the Bedrock block entity and are updated when that block entity changes, so an already filled frame and a newly filled frame both render.
• Chunk palette lookup: Frame detection must use the original Bedrock palette indices. Java block-state remapping can reorder or coalesce the copied palette. Reading Bedrock tags through those remapped indices selected the wrong block state and caused the observed frame disconnect.
• Click handling: The Java frame entity is synthetic and has no Bedrock actor ID. Its Java entity ID now maps back to the Bedrock frame block. Clicking it sends the existing Bedrock block-use transaction, including the selected item and face, instead of trying to look up a nonexistent Bedrock actor. The shared transaction helper keeps ordinary block use and frame use on the same path. Removing a frame clears both lookup directions.
• Code placement and tests: The old experimental map translator and its storage were removed because map updates must work in the normal protocol path. JUnit dependencies support focused color conversion tests, including two nearby palette colors that collided in the old cache.

Verification

• ./gradlew build --offline --no-daemon passes, including the color conversion tests.
• On an isolated Bedrock 1.26.51 test server through ViaProxy, the Java client displayed a filled map in hand and in a newly placed frame. The user confirmed the frame worked without disconnecting and supplied a screenshot showing both maps.
• A native Bedrock client joined the separate NetherNet test server and placed a filled map in a frame. Java and native Bedrock were tested on separate local server instances because the current unauthenticated ViaProxy NetherNet offer is rejected at signaling, before ViaBedrock receives gameplay packets. Cross-client viewing of the same NetherNet world remains unverified.

[AlexProgrammerDE]

Only blocker on this right now is I gotta figure out if maps actually have the right colors for some blocks.
Mossy cobblestone looked kinda teal

[AlexProgrammerDE]

Bedrock:

Java: