feat(ahbg): extract validated presentation-only board

.github/workflows/ahbg-presentation.yml

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+name: ahbg-presentation
+
+on:
+  pull_request:
+    paths:
+      - "ahbg/presentation/**"
+      - ".github/workflows/ahbg-presentation.yml"
+  push:
+    branches: [main]
+    paths:
+      - "ahbg/presentation/**"
+      - ".github/workflows/ahbg-presentation.yml"
+
+permissions:
+  contents: read
+
+jobs:
+  presentation:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - uses: actions/setup-python@v6
+        with:
+          python-version: "3.12"
+      - name: Python presentation contract
+        run: python -m unittest discover -s ahbg/presentation/tests -p 'test*.py'
+      - name: Browser JavaScript syntax
+        run: node --check ahbg/presentation/board.js

ahbg/presentation/README.md

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+# AHBG presentation
+
+Grok-owned graphics surface. It renders validated presentation snapshots and
+already-resolved motion traces. It does **not** define game mechanics or derive
+UCNS geometry.
+
+## Boundary
+
+- Included: Seed-of-Life circle rendering, UCNS-supplied tile centerpoints,
+  unit markers, selection/inspection, public feed text, and visual traces of
+  already-resolved moves.
+- Excluded: legal movement, adjacency authority, turns, War resolution,
+  construction, permissions, RNG, DM state, private prompt state, or agent policy.
+- Snapshot standing is `ahbg.presentation.snapshot` / `not-mechanics`.
+- Every snapshot carries an exact `geometry_source` identity plus each tile's
+  UCNS-derived `x`, `y`, and `source_slot`. The renderer only scales those
+  coordinates for SVG display; it never rebuilds centers from local axial rules.
+- The current sample pins `The-Interdependency/ucns@1975fe70cf4e0826a8020c2da3047569e277af64`,
+  the canonical `libs/ucns/` identity in the stack manifest when this surface was
+  authored. Its `mobius_seed` module remains an explicit nonselecting UCNS
+  candidate; presentation consumption does not promote its standing.
+- `project.py` accepts already-sanitized observation data, source-backed display
+  coordinates, and resolved move events. It never decides whether those moves
+  were legal and copies only declared browser-facing fields.
+- `geometry.py` scales supplied source coordinates into display pixels only.
+
+## Usage guidance
+
+Validate the package:
+
+```bash
+python -m unittest discover -s ahbg/presentation/tests -p 'test*.py'
+node --check ahbg/presentation/board.js
+```
+
+Serve the board locally:
+
+```bash
+cd ahbg/presentation
+python -m http.server 8765 --bind 127.0.0.1
+# open http://127.0.0.1:8765/board.html
+```
+
+Project a sanitized observation only after the owning adapter has attached the
+UCNS-derived centers and exact source identity:
+
+```python
+from ahbg.presentation.project import snapshot_from_observation
+
+geometry_source = {
+    "repository": "The-Interdependency/ucns",
+    "commit": "1975fe70cf4e0826a8020c2da3047569e277af64",
+    "module": "src/ucns/mobius_seed.py",
+    "schema_id": "ucns.mobius-seed-of-life",
+    "schema_version": "0.1.0",
+    "projection_id": "seed-of-life-seven-equal-circles",
+    "selection_effect": "none",
+}
+observation = {
+    "turn": 1,
+    "geometry_source": geometry_source,
+    "tiles": [
+        {"tile_id": "CENTER", "ucns_slot": "CENTER", "x": 0.0, "y": 0.0},
+        {"tile_id": "RING_0", "ucns_slot": "RING_0", "x": 1.0, "y": 0.0},
+    ],
+    "units": [{"unit_id": "A0", "tile_id": "RING_0", "label": "A0"}],
+}
+move = {
+    "kind": "move",
+    "data": {"unit_id": "A0", "from_tile_id": "CENTER", "to_tile_id": "RING_0"},
+}
+snapshot = snapshot_from_observation(
+    observation,
+    plane_id="plane-0",
+    move_events=[move],
+    feed=[{"turn": 1, "text": "public display text only"}],
+)
+```
+
+The snapshot validator is allowlist-based. Unknown root, geometry, tile, unit,
+feed, or motion fields fail closed. The projector drops undeclared observation,
+move-event, and feed metadata before validation, preventing a visual snapshot
+from becoming a transport for private/internal fields.
+
+The browser exposes tile inspection to pointer and keyboard input, permits
+interactive descendants under an SVG `group` role, scales unit-marker spread by
+occupant count, and renders the selection ring above the unit layer.
+
+## hmmm
+
+- whether later Flower-of-Life rings belong on this presentation surface;
+- the exact live engine-to-observation adapter that attaches UCNS positions is
+  owned by the eventual engine integration, not by this graphics package;
+- construction animation remains unavailable until an owning mechanics layer
+  emits an already-resolved construction event contract.

ahbg/presentation/__init__.py

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+# === MODULE_BUILD ===
+# id: ahbg_presentation_public_boundary
+#   module_name: presentation
+#   module_kind: adapter
+#   summary: exposes the validated presentation snapshot and projection boundary without exporting mechanics
+#   owner: AHBG presentation
+#   public_surface: PresentationSnapshotError, load_snapshot, snapshot_from_observation, validate_snapshot
+#   internal_surface: none
+#   auth_boundary: none
+#   storage_boundary: none
+#   network_boundary: none
+#   user_data_boundary: none
+#   admin_only: false
+#   tests: ahbg/presentation/tests/test_presentation.py
+#   rollout: import explicitly from ahbg.presentation
+#   rollback: remove package exports with presentation package
+#   requires: ahbg_presentation_snapshot_contract, ahbg_presentation_observation_projector
+#   since: 2026-08-31
+#   unresolved: none
+# === END MODULE_BUILD ===
+
+"""Presentation-only AHBG graphics boundary.
+
+Usage guidance: import only validated presentation helpers from this package;
+game mechanics remain outside this namespace.
+"""
+
+from .project import snapshot_from_observation
+from .snapshot import PresentationSnapshotError, load_snapshot, validate_snapshot
+
+__all__ = [
+    "PresentationSnapshotError",
+    "load_snapshot",
+    "snapshot_from_observation",
+    "validate_snapshot",
+]

ahbg/presentation/board.css

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+:root {
+  --ink: #1b1a17;
+  --paper: #f4efe4;
+  --tile: #e6dcc8;
+  --tile-stroke: #6b5d44;
+  --selected: #c45c26;
+  --unit: #1f4b99;
+}
+
+html,
+body {
+  margin: 0;
+  background: var(--paper);
+  color: var(--ink);
+  font: 16px/1.4 "Iowan Old Style", "Palatino Linotype", Palatino, serif;
+}
+
+main {
+  display: grid;
+  grid-template-columns: minmax(0, 1fr) 18rem;
+  min-height: 100vh;
+}
+
+.board-wrap { display: flex; flex-direction: column; padding: 1.5rem; }
+h1, h2 { font-weight: 600; letter-spacing: 0.04em; margin: 0 0 0.75rem; }
+.note { margin: 0 0 1rem; font-size: 0.95rem; }
+svg { width: min(100%, 36rem); height: auto; align-self: center; }
+.seed-circle { fill: none; stroke: var(--tile-stroke); stroke-width: 1.5; pointer-events: none; }
+.tile-point { fill: var(--tile-stroke); stroke: var(--paper); stroke-width: 1.5; pointer-events: none; }
+.tile-point.selected { fill: var(--selected); stroke: var(--selected); }
+.motion-path { fill: none; stroke: var(--selected); stroke-width: 2.5; stroke-dasharray: 6 4; pointer-events: none; }
+.tile-hit { fill: transparent; cursor: pointer; stroke: transparent; stroke-width: 3; }
+.tile-hit:focus { outline: none; stroke: var(--selected); }
+.tile-label { fill: var(--ink); font-size: 11px; pointer-events: none; text-anchor: middle; }
+.unit { fill: var(--unit); stroke: var(--paper); stroke-width: 2; pointer-events: none; }
+.unit-label { fill: var(--paper); font-size: 10px; pointer-events: none; text-anchor: middle; }
+.selection-ring { fill: none; stroke: var(--selected); stroke-width: 3; pointer-events: none; }
+.feed { background: #efe7d6; border-left: 1px solid var(--tile-stroke); padding: 1.5rem; }
+.feed ol { margin: 0; padding-left: 1.2rem; }
+.inspect { margin-top: 1rem; font-size: 0.95rem; }
+
+@media (max-width: 720px) {
+  main { grid-template-columns: 1fr; }
+  .feed { border-left: 0; border-top: 1px solid var(--tile-stroke); }
+}

ahbg/presentation/board.html

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+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <title>AHBG presentation board</title>
+    <link rel="stylesheet" href="board.css" />
+  </head>
+  <body>
+    <main>
+      <section class="board-wrap">
+        <h1>AHBG plane</h1>
+        <p class="note">Presentation only. Not mechanics. Tile centers are supplied by the declared UCNS source; the browser only scales them for display. Dashed traces show already-resolved motion. Click a center, or focus it and press Enter/Space, to inspect.</p>
+        <svg id="board" role="group" aria-label="Interactive Seed of Life presentation with inspectable tile centers and resolved unit motion traces"></svg>
+      </section>
+      <aside class="feed">
+        <h2>Feed</h2>
+        <ol id="feed-list"></ol>
+        <p class="inspect" id="inspect" aria-live="polite"></p>
+      </aside>
+    </main>
+    <script src="board.js"></script>
+  </body>
+</html>