Expand material support and checkpoint the completed building toolkit

Expose the runtime block/item registry through compact material search and
single-material descriptions. Preserve private block-entity data through
checked edits and durable undo without sending payloads to model context.

Include the completed terrain tools, isolated world/map plugin, station lift,
ACP streaming and guidance fixes, local camera auto-connect, construction
scripts, and their public documentation, references and verification records.
Active station decoration and private runtime data remain outside this commit.

Validation: 145 Maven tests, 47 Bridge tests, successful camera Gradle build,
and isolated Paper verification of all 1,196 block defaults plus 5,392
independent property cases for placement, same-material edits and restoration.

docs/references/shacraft-natural-v2-generation-report.json

@@ -0,0 +1,11 @@
+{
+  "elapsed_ms": 274728,
+  "max_surface_y": 204,
+  "min_surface_y": 48,
+  "water_columns": 42399,
+  "mismatches": 0,
+  "chunks": 2304,
+  "recipe_id": "fed10bf28fa544e7dba08d10c76a1130c67292856999b06a9fd672feeed39296",
+  "verified_columns": 589824,
+  "world": "shacraft_lobby_v2"
+}