Implement HexGame placement canvas (governance)

name: HexGame Placement Docs overview: Codify the HexGame→Novolis placement canvas as an informative governance ideal and wire it into existing boundary policies, without importing HexGame NuGet or adding Game.Intent/Frame packages yet. todos:

• id: ideal-doc

content: Add architectural-ideals/hexgame-authoritative-core.md from placement canvas (stack roles, composition, deferred, conformance checklist) status: completed

• id: cross-links

content: Cross-link from library-boundaries, simulation-layer-policy, gaming-layer-policy, gameengine-reference-policy, platform-library-boundaries.mdc status: completed

• id: ideals-index

content: Add short ideals folder index entries in architectural-ideals/README.md status: completed

• id: verify-wording

content: Review for Tick→Simulation (not Physics), no HexGame NuGet, no GameKit language status: completed isProject: false

Scope (locked)

Implement the canvas’s recommended move order steps 1–3 as documentation and agent-facing policy:

1. Informative HexGame ideal with Math → Physics → Simulation made explicit
2. Application cores stay in apps and drive Simulation
3. Physics is only a callee from sim/domain steps

Out of scope for this change: Novolis.Game.Intent, Simulation FrameSnapshots, Multiplayer host glue packages, vendoring HexGame.*, and dogfood app refactors. Those remain deferred until multiple apps share a shape (per the canvas).

Source of truth for content: hexgame-novolis-placement.canvas.tsx. External reference: frankhaugen/HexGame (informative only — not Novolis law).

Deliverable 1 — Architectural ideal

Add d:\novolis\novolis-governance\docs\architectural-ideals\hexgame-authoritative-core.md, styled like workspace-snapshot-timeline.md:

• Purpose: HexGame-shaped games on Novolis without HexGame packages or a GameKit layer
• Non-goals: Not an IETF/BCP 14 Novolis RFC; not a mandate to PackageReference HexGame; not Stride Lite
• Stack roles table: Math / Physics / Simulation / Apps / Raylib·Rendering / Gaming — matching library-boundaries.md
• Hard rule: HexGame Tick / command dispatch / world systems / replay / presentation snapshots → Simulation + app; Physics must not own tick order (call out that Novolis.Physics.Motion.SimulationPipeline is an integrator pipeline name, not orchestration)
• Composition table: app owns IGameApplication-shaped API → Simulation clock/systems → optional Physics inside systems → host adapters (Raylib/Silk) → presenters
• Package map: existing homes only (Simulation.*, Physics.* as callee, Raylib.Hosting, Game.Identity/Multiplayer, Commands.* vs player intent, Snapshots.* vs sim replay)
• Deferred: Game.Intent, shared frame DTOs under Simulation.Abstractions, FrameSnapshots — with exit criteria (“2–3 apps share envelope”)
• Conformance checklist (for dogfood/PR review): engine objects not save state; local authority via same core; Physics not tick owner; no HexGame NuGet in platform csproj; gaming has no sim/raylib refs

flowchart TD
  inputAdapter[InputAdapter]
  appCore[App_IGameApplication]
  sim[Novolis_Simulation]
  phys[Novolis_Physics]
  present[Presenters_Hosts]
  inputAdapter -->|"commands_intents"| appCore
  appCore -->|"Advance_Tick"| sim
  sim -->|"optional_physical_dt"| phys
  appCore -->|"snapshot_effects"| present

Deliverable 2 — Cross-links (policy glue)

Short “Related” / one-paragraph pointers only — do not duplicate the full ideal:

No new Cursor skill/agent unless the ideal is large enough to warrant it; the existing boundaries rule + new doc are enough for agents.

Deliverable 3 — Index hygiene

architectural-ideals/README.md currently mirrors the distributed-services guideline index. Add a short Ideals in this folder list at the top (or a separate index.md if rewriting README would be too disruptive) linking:

• hexgame-authoritative-core.md
• workspace-snapshot-timeline.md
• distributed-services-architectural-guideline.md

Prefer a minimal top-of-README index to avoid relocating the distributed-services content in this change.

Verification

• Links resolve within novolis-governance
• Wording does not invent Novolis.HexGame.* or authorize HexGame PackageReferences
• Physics section of the ideal cannot be read as “put simulation in Physics”
• No csproj / package map / Generate-Platform-Slnx changes in this PR

Follow-ups (documented only, not implemented)

Record in the ideal’s Deferred section: extract Novolis.Game.Intent after shared command envelopes; shared frame DTOs only under Novolis.Simulation.Abstractions; never grow orchestration under Physics.