docs: move task list to TODO.md and keep ROADMAP.md as plan

Split the former ROADMAP.md checklists into TODO.md, which now holds
all actionable work and progress marks. ROADMAP.md keeps milestone
goals, scope, and release gates as prose with no checkboxes.

Update AGENTS.md, Docs/, Geo/README.md, MEMORY.md, and README.md to
point to the new file roles.

README.md

@@ -6,7 +6,7 @@ A Linux-first Unreal Engine game about walking and driving through a real city.
 
 `0.1.0` is in progress. The workstation, engine, geo pipeline and project bootstrap are done and verified; a walkable `DemoMap` exists with terrain, street, sidewalks, kerbs and the hero façade placed from measured coordinates. Façades are still blockouts, and materials are flat colours — both are planned patches.
 
-Current state is in [ROADMAP.md](ROADMAP.md); what was learned the hard way is in [MEMORY.md](MEMORY.md).
+Current tasks are in [TODO.md](TODO.md) and the development plan is in [ROADMAP.md](ROADMAP.md); what was learned the hard way is in [MEMORY.md](MEMORY.md).
 
 ## Layout
 
@@ -31,7 +31,8 @@ The engine is installed outside the repository and pinned in [Docs/toolchain.md]
 
 ## Documents
 
-- [ROADMAP.md](ROADMAP.md) — living task list, source of truth for progress
+- [TODO.md](TODO.md) — living task list, source of truth for progress
+- [ROADMAP.md](ROADMAP.md) — development plan: milestone goals, scope, and release gates
 - [MEMORY.md](MEMORY.md) — shared session memory: discoveries, traps, decisions
 - [AGENTS.md](AGENTS.md) — contributor and agent rules
 - [PLAN.md](PLAN.md) — scope, stack, release policy, timeline