docs(arch): realism leads the quality list; performance moves to the end

Owner decision: prioritise realism, keep the performance target but put it last.
Re-applied on a branch after the first attempt landed directly on main (reverted
there; see b8209ce).

- Quality goals (01 + combined architecture.md): 1 visual realism, 2 geographic
  fidelity, 3 walkability/usability, 4 reproducibility/portability, 5 provenance,
  6 performance efficiency.
- Quality requirements (10 + combined) reordered to match, with two realism
  requirements added (a façade reads like the photographs; placement within ~1 m)
  and the scenarios renumbered so QS-1 is the reference comparison, QS-9 the frame
  rate.
- Guard on both documents so the order cannot become an excuse: performance is a
  floor, not a preference - 60 FPS at 1440p without frame generation must be met at
  every release; if realism cannot fit, cut the realism scope deliberately and
  record it, never the frame rate. Walkability outranks realism in one direction: a
  block you fall through is not a demo.
- Solution strategy and 'quality achievement' lead with realism and describe
  performance as a budget, not a driver.
- Docs/release-checks.md: the performance check is the last section and the per-
  version check list now opens with realism and closes with performance.
- ROADMAP gains a 'Quality priority' section; AGENTS.md gains the tie-break rule
  beside the existing scope-cutting rule.

ROADMAP.md

@@ -2,6 +2,10 @@
 
 Development roadmap for this project: milestone goals, scope, decisions, and release gates. Actionable tasks, claims, and progress marks live in [TODO.md](TODO.md).
 
+## Quality priority
+
+**Realism leads; performance is a floor.** Façade identity, proportion, material and light are judged against the reference photographs and drive design decisions. Performance closes the quality list: 60 FPS at 1440p without frame generation is a budget every release must meet, and if realism cannot fit inside it the realism scope is cut deliberately and recorded — never the frame rate.
+
 ## Status at a glance — 2026-11-08 15:30
 
 Workstation, geo pipeline, and engine validation are done. The art pipeline has a first blockout, terrain, and street in metres, in one shared coordinate frame. **Project bootstrap is complete**: `Game/GigLine` builds, packages, and both content-acceptance tests (static-mesh scale, MPFB skeletal character) pass. **`v0.1.0` released 2026-11-08**: the walkable demo, hero façade, verified block frontage, first-person controls, ODbL attribution, and every release check pass (traversal, placement, collision, 60 fps at 1440p, fresh-checkout build, packaged build with controls). Next: the `0.1.1`–`0.1.4` patch series (collision detail, scale/façade corrections, packaging fixes, real building façades), then `0.2.0` (player body, third-person camera, animation).