feat: first-person player with Enhanced Input

AGigLineCharacter: 1.75 m capsule, 1.60 m eye camera, 4 m/s walk, mouse look
scaled in degrees per second (no double DeltaTime), jump. Loaded ahead of a
Blueprint so the demo is playable with no assets wired by hand.

Tools/ue_create_input_assets.py builds /Game/Input headlessly: five 1D actions
and an 11-mapping context. One action per direction instead of per-key modifiers,
because modifier objects do not survive the save path here: a mapping's modifier
array serialises None, and dimensioning a 2D move with per-key axis masks would
need exactly those modifiers. The cost is four action assets rather than two.

Also adds a fourth review camera at eye height and documents it; its approval is
pending.

AGENTS.md

@@ -92,7 +92,9 @@ New content that needs a different camera angle gets a new entry in the shot lis
 
 The living roadmap with per-version task checklists is in **[ROADMAP.md](ROADMAP.md)**.
 
-- Planned work is listed as checkbox items in `ROADMAP.md`, each marked **open** (`- [ ]`), **in progress** (`- [-]`), or **done** (`- [x]`). Update the marks as work changes state; a checkbox that no longer matches reality is worse than none.
+- `ROADMAP.md` is the single, central TODO and progress list for all agents. Put planned work and actionable follow-ups there rather than creating parallel task lists.
+- When working on a level-three (`###`) section, append ` - active - <sessionId>` to its heading, using your current session ID. Remove the suffix when you stop working on that section. Mark checklist items currently being worked on `- [-]` or `- [~]`; update the marks as their status changes.
+- Planned work is listed as checkbox items in `ROADMAP.md`, marked **open** (`- [ ]`), **in progress/active** (`- [-]` or `- [~]`), or **done** (`- [x]`). Keep the marks accurate.
 
 - Each version is a `##` heading; task groups are `###` headings with `- [ ]` steps (`[-]` in progress, `[x]` done).
 - When **all** steps in a version section are done: write a short descriptive entry to `CHANGELOG.md`, then remove the version section from `ROADMAP.md` to keep it concise.
@@ -101,7 +103,7 @@ The living roadmap with per-version task checklists is in **[ROADMAP.md](ROADMAP
 
 ## Memory
 
-**[MEMORY.md](MEMORY.md)** is the shared working memory between sessions and collaborators. Write to it whenever you:
+**[MEMORY.md](MEMORY.md)** is shared session memory for agents and collaborators. Write to it whenever you:
 
 - discover a fact about the environment, a tool, or a data source that cost time to establish;
 - hit a gotcha, trap, or surprising failure mode, and what actually caused it;