feat: add live replays and PostgreSQL maintenance tools

- Stream compact live replay updates across local and clustered dashboards.
- Render responsive snake bodies as SVG paths with aligned custom icons.
- Add cache-busted assets, replay fallback routes, and live-follow playback.
- Support PostgreSQL benchmark sampling and idempotent SQLite migration.
- Add dry-run cleanup for old low-quality PostgreSQL replay payloads.
- Reward safe perimeter lanes and bump Prism to version 1.5.0.
- Add backend, migration, dashboard, and perimeter regression coverage.

justfile

@@ -62,13 +62,33 @@ bench-best-snake iterations="1000":
 
   PYTHONPATH="{{justfile_directory()}}" python "{{justfile_directory()}}/tests/bench_best_battle_snake.py" --iterations "{{iterations}}"
 
-bench-snake-arena positions="100" output="":
+bench-snake-arena positions="100" output="" database="":
   #!/usr/bin/env bash
   set -euo pipefail
 
   args=(--positions "{{positions}}")
+  if [ -n "{{database}}" ]; then args+=(--database "{{database}}"); fi
   if [ -n "{{output}}" ]; then args+=(--json-output "{{output}}"); fi
-  PYTHONPATH="{{justfile_directory()}}" python "{{justfile_directory()}}/scripts/benchmark_snake_arena.py" "${args[@]}"
+  PYTHONPATH="{{justfile_directory()}}" uv run python "{{justfile_directory()}}/scripts/benchmark_snake_arena.py" "${args[@]}"
+
+bench-snake-arena-postgres positions="100" output="":
+  #!/usr/bin/env bash
+  set -euo pipefail
+
+  : "${GAMEPLAY_DB_PG_DSN:?Set GAMEPLAY_DB_PG_DSN in .env or the environment}"
+  args=(--positions "{{positions}}" --database "$GAMEPLAY_DB_PG_DSN")
+  if [ -n "{{output}}" ]; then args+=(--json-output "{{output}}"); fi
+  PYTHONPATH="{{justfile_directory()}}" uv run python "{{justfile_directory()}}/scripts/benchmark_snake_arena.py" "${args[@]}"
+
+cleanup-gameplay-postgres older_than_days="30" execute="false" vacuum="false":
+  #!/usr/bin/env bash
+  set -euo pipefail
+
+  : "${GAMEPLAY_DB_PG_DSN:?Set GAMEPLAY_DB_PG_DSN in .env or the environment}"
+  args=(--dsn "$GAMEPLAY_DB_PG_DSN" --older-than-days "{{older_than_days}}")
+  if [ "{{execute}}" = "true" ]; then args+=(--execute); fi
+  if [ "{{vacuum}}" = "true" ]; then args+=(--vacuum); fi
+  PYTHONPATH="{{justfile_directory()}}" uv run python "{{justfile_directory()}}/scripts/cleanup_postgresql_gameplay.py" "${args[@]}"
 
 bench-snake-tournament games="20" gametype="standard" map="standard" output="":
   #!/usr/bin/env bash
@@ -109,6 +129,19 @@ battlesnake-cli-version:
 #  Testing helpers
 # ------------------------------------------------------------------------------
 
+test-unit:
+  #!/usr/bin/env bash
+  set -euo pipefail
+
+  PYTHONPATH="{{justfile_directory()}}" python -m unittest discover -s "{{justfile_directory()}}/tests" -p "test_*.py"
+
+# Dashboard front-end logic (head/tail orientation, board geometry).
+test-js:
+  #!/usr/bin/env bash
+  set -euo pipefail
+
+  node --test "{{justfile_directory()}}"/tests/js/*.test.mjs
+
 test-constrictor: build-battlesnake-cli
   #!/usr/bin/env bash
   set -euo pipefail