feat(pages): filter and group the landing page by subject

The landing page had grown to 55 simulations in three fixed lineage
buckets. Add a toolbar with subject chips (Physics, Chemistry, Astronomy,
Earth Science) with live counts, a search box over names, descriptions
and all topics, a collection filter, and a group-by control (subject,
collection, or A-Z). The view state is mirrored in the query string so
filtered views can be shared. Without JS the page renders grouped by
subject.

Catalog: add a required `subject` to every simulation (schema 1.4.0),
enforced by check-repos-catalog.sh; create-sim.sh gains --subject
(default physics).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: veillette

README.md

@@ -33,7 +33,7 @@ Pages simulation landing page.
 | [`screenshots/`](screenshots/) | Full-size sim screenshots the landing-page thumbnails are made from |
 | [`config/`](config/) | Canonical Dependabot, Claude-settings, and GitHub-repo-settings baselines |
 | [`structure/repos.json`](structure/repos.json) | Machine-readable catalog of org repositories |
-| [`structure/repos.schema.json`](structure/repos.schema.json) | JSON Schema for the catalog (`schemaVersion` 1.3.0) |
+| [`structure/repos.schema.json`](structure/repos.schema.json) | JSON Schema for the catalog (`schemaVersion` 1.4.0) |
 | [`CONVENTIONS.md`](CONVENTIONS.md) | Shared codebase structure every SceneryStack sim must follow |
 | [`ACCESSIBILITY.md`](ACCESSIBILITY.md) | Shared accessibility pattern for SceneryStack sims |
 | [`skills/`](skills/) | SceneryStack development reference docs for AI assistants |

doc/add-simulation.md

@@ -70,6 +70,7 @@ Edit [`structure/repos.json`](../structure/repos.json). Insert a new object in `
   "type": "simulation",
   "isSimulation": true,
   "lineage": "original",
+  "subject": "physics",
   "upstream": null,
   "language": ["TypeScript"],
   "framework": "SceneryStack",
@@ -90,6 +91,7 @@ Edit [`structure/repos.json`](../structure/repos.json). Insert a new object in `
 | `name` | Must match the GitHub repo name (and the sibling folder name in the workspace). |
 | `displayName` | Human title on the landing-page card (and for docs). |
 | `lineage` | Landing-page bucket: `"original"`, `"phet"`, or `"naap"`. Non-simulations use `null`. |
+| `subject` | Required for simulations: `"physics"`, `"chemistry"`, `"astronomy"`, or `"earth-science"`. Drives the landing page's subject filter and default grouping. `create-sim.sh --subject` sets it (default `physics`). |
 | `upstream` | For `phet` / `naap` ports: `{ "org", "name", "url" }` pointing at the source lab. Otherwise `null`. |
 | `description` | Full blurb on the Pages card. |
 | `shortDescription` | Optional. GitHub About text (≤350 chars). When omitted, metadata sync uses `description` (truncated if needed). |

docs/index.html

@@ -78,6 +78,13 @@ assert_jq "simulations have lineage + non-empty screens" '
   )
 '
 
+assert_jq "simulations have a known subject" '
+  all(.repos[] | select(.isSimulation);
+    (.subject == "physics" or .subject == "chemistry" or .subject == "astronomy"
+     or .subject == "earth-science")
+  )
+'
+
 assert_jq "simulations have non-empty physicsTopics" '
   all(.repos[] | select(.isSimulation);
     (.physicsTopics | type == "array" and length > 0)

scripts/check-repos-catalog.sh

@@ -29,6 +29,7 @@ SIM_ID=""
 SIM_NAME=""
 SCREENS=""
 TOPICS=""
+SUBJECT="physics"
 GITHUB_TOPICS=""
 TARGET_PATH=""
 LOCAL_ONLY=0
@@ -57,6 +58,8 @@ Options:
                        Default: one screen named after --name.
                        Catalog stores {id, title} (id from kebab: or slug of title).
   --topics LIST        Comma-separated physicsTopics (required with --catalog/--onboard)
+  --subject SUBJECT    Landing-page discipline: physics (default), chemistry,
+                       astronomy, or earth-science
   --github-topics LIST Optional extra GitHub topics (kebab-case), e.g. game,pwa
   --shared-model       Scaffold src/common/model/SharedModel.ts; each screen composes it
   --path DIR           Checkout path (default: $FLEET_WORKSPACE/<repo>)
@@ -329,6 +332,10 @@ while [[ $# -gt 0 ]]; do
       TOPICS="${2:?Missing value for --topics}"
       shift 2
       ;;
+    --subject)
+      SUBJECT="${2:?Missing value for --subject}"
+      shift 2
+      ;;
     --github-topics)
       GITHUB_TOPICS="${2:?Missing value for --github-topics}"
       shift 2
@@ -525,6 +532,14 @@ if [[ "$CATALOG" -eq 1 || "$ONBOARD" -eq 1 ]]; then
   fi
 fi
 
+case "$SUBJECT" in
+  physics | chemistry | astronomy | earth-science) ;;
+  *)
+    echo "error: --subject must be physics, chemistry, astronomy, or earth-science (got '$SUBJECT')" >&2
+    exit 1
+    ;;
+esac
+
 if [[ -n "$SHORT_DESCRIPTION" && ${#SHORT_DESCRIPTION} -gt 350 ]]; then
   echo "error: --short-description must be ≤350 characters (got ${#SHORT_DESCRIPTION})" >&2
   exit 1
@@ -536,6 +551,7 @@ echo "  name:     $SIM_NAME"
 echo "  path:     $TARGET_PATH"
 echo "  screens:  ${SCREENS:-"(default: $SIM_NAME)"}"
 echo "  topics:   ${TOPICS:-"(none)"}"
+echo "  subject:  $SUBJECT"
 echo "  shared:   $([[ "$SHARED_MODEL" -eq 1 ]] && echo yes || echo no)"
 echo "  onboard:  $([[ "$ONBOARD" -eq 1 ]] && echo yes || echo no)"
 echo "  existing: $([[ "$EXISTING" -eq 1 ]] && echo "yes (adopt already-on-GitHub repo)" || echo "no (create from template)")"
@@ -646,6 +662,7 @@ entry="$(jq -n \
   --arg desc "$DESCRIPTION" \
   --arg short "$SHORT_DESCRIPTION" \
   --arg url "${PAGES_BASE}/${REPO}" \
+  --arg subject "$SUBJECT" \
   --argjson screens "$catalog_screens_json" \
   --argjson topics "$catalog_topics_json" \
   --argjson githubTopics "$catalog_github_topics_json" \
@@ -656,6 +673,7 @@ entry="$(jq -n \
       type: "simulation",
       isSimulation: true,
       lineage: "original",
+      subject: $subject,
       upstream: null,
       language: ["TypeScript"],
       framework: "SceneryStack",