npc: AGigLineNPCPerson prefab + stable-named screenshots

- New C++ AGigLineNPCPerson: reusable NPC/pedestrian prefab built on the MPFB
  human. ACharacter capsule half-height 83 cm (total 1.66 m, head top ~1.66 m
  so a 1.60 m camera doesn't clip), the character skeletal mesh on the built-in
  mesh as the visible body (feet on Z 0), AutoPossessAI for 0.5.0 pedestrians.
  Staged at Z 0 in the review scene; captured as review-npc-prefab.png.
- AGigLineShotActor now names screenshots by stable camera name (no list-index
  prefix): inserting or reordering cameras no longer renumbers files or orphans
  the old ones. Re-rendered all review/demo shots with stable names.
- ue_build_review_map.py: chmod the target .umap before save_map (git marks maps
  444 on checkout, silently making save_map return False and dropping stages).
- Screenshots/README.md, ROADMAP, TODO updated for the prefab + stable names.
- DemoMap.umap rebuilt by the render pipeline (north buildings + demo cameras).

ROADMAP.md

@@ -28,7 +28,7 @@ Workstation, geo pipeline, and engine validation are done. The art pipeline has
 
 **Geographic data (complete, with blockout detail open):** the OSM extract, address, footprints, demo bounds, EPSG:26911 frame with a recorded origin, and the 3DEP 1 m DEM are verified and committed. The meter→centimetre conversion lives in one function, and every exporter must call it. Block buildings still need height data for three placeholders and cleaning or detailing of the Blosm blockout.
 
-**Review and character (decision):** the review scene is the staging used for all visual approval. Its scope is the character's ground contact, the camera list, and the façade detail shots, and nothing in asset production or gameplay continues past it until these shots pass. The shot list is in `Screenshots/README.md`. Coordinator decision 2026-11-07: **`0.1.0` ships first-person only**, a capsule with a camera and no visible player body. The MPFB character asset (idle pose, warm skin) is the template for later **NPCs** (`0.2.0` body/camera toggle, `0.5.0` pedestrians). It stays a standalone character prefab, not wired into the `AGigLineCharacter` pawn.
+**Review and character (decision):** the review scene is the staging used for all visual approval. Its scope is the character's ground contact, the camera list, and the façade detail shots, and nothing in asset production or gameplay continues past it until these shots pass. The shot list is in `Screenshots/README.md`. Coordinator decision 2026-11-07: **`0.1.0` ships first-person only**, a capsule with a camera and no visible player body. The MPFB character asset (idle pose, warm skin) is the template for later **NPCs** (`0.2.0` body/camera toggle, `0.5.0` pedestrians). It is now a concrete reusable prefab, `AGigLineNPCPerson` (collision capsule + visible body, feet on Z 0), kept standalone and not wired into the `AGigLineCharacter` pawn.
 
 **Asset production:** the scale test and the `ue_metric_v1` export and import presets are established. The hero façade first pass is built and screenshot-approved; the north-side buildings (TCL Chinese Theatre, Madame Tussaud's) are staged. Open: reference collection for the door recess and the night frame, the surrounding block frontage, sidewalks, roads and collision, and materials for all assets.