Remaster fifteen original pictures with reproducible artwork cleanup

Add the final boss picture, three coherent terrain remasters and complete DSHP20G3/WORMRITE catalogue families. Preserve generated parents, portable recipes, derivation receipts and separate artistic/context reviews.

Validate 5500 HD pictures with zero rejects and all 45 mods. Review three unchanged 1080p SDL controls, preserve existing runtime/data bindings, and update Linux/Windows shared-data metadata and progress records. Cleanup tools pass 101 tests plus 12 TARGT input-safety tests; TARGT artwork remains pending.

README.md

@@ -82,8 +82,8 @@ are tracked in Git, along with mod definitions, scripts, SD/HD PNGs, WAVs,
 generation prompts and recipes. Build caches and local review files are excluded.
 See [repository layout](docs/repository.md).
 The engine supports original rendering and crisp 2×/3×/4× scaling, plus an
-optional HD artwork setting. The reviewed base-game pack now covers **5,485 of
-5,753 original pictures**, with **268 still awaiting approval**. All 307 native
+optional HD artwork setting. The reviewed base-game pack now covers **5,500 of
+5,753 original pictures**, with **253 still awaiting approval**. All 307 native
 AGX cinematic/font records remain preserved separately. Bundled mods include
 SD/HD artwork. [The HD backlog](docs/hd-backlog.md) records the remaining
 originals, held drafts and review limits.