[KunalSiyag]

What

Phase B step 3 of the web split-pack plan (docs/round3/web/phase-b-runtime-plan.md implementation order): Option A export classification tests + the runtime request/arrival hooks. Builds on #91 (loader hardening + WebPackStream, flag still off).

Runtime hooks

• CityView asks WebPackStream.request_path() on an asset miss before any ResourceLoader.exists/cache decision (_scene, warm_scenes, _warm_one all route through one _pack_gate). A pending pack returns null without writing the cache, so a download in flight no longer poisons _scenes with a permanent null; the wait is recorded per pack.
• On pack_ready, exactly the recorded paths are retried (warm_scenes), stale null entries are dropped, and loaded scenes keep their tuned materials. Genuine misses (no pack claims the path) and stream-less desktop runs keep the exact old behavior.
• The one boot-side caller with its own exists() guard that could never register a miss — the tree props in _make_tree_kits, which ride in the props pack — now demands through the gate. Re-kitting chunks on arrival is part of the step-4 feature coverage.
• FpContext.pack_stream (filled before player/collision/feature setup), GameBus.pack_ready(pack), FpMode forwards coordinator arrivals onto the bus and disconnects on teardown.
• midlod demands the midlod pack on a baked-twin miss, keeps completed runtime twins across arrival (no _meshes/_jobs clearing, no _activate), and lets fresh mesh_for calls pick up baked files. render_opt passes the stream through.

Export classification (Option A pinned as tests)

• tools/pytests/test_pack_closure.py: zone/service geometry, hero bodies/animation/roster/bonemaps, textures, fonts, UI sounds and all unmatched paths classify to boot; the eight decorative packs classify as background; BOOT_PATHS wins over prefix rules.
• A project-wide closure test fails on any static cross-pack reference (preload, class-level load, scene ext_resource) — the boot pack can never statically depend on a download. Current tree: zero violations.
• A parity test keeps PACK_RULES pack names inside WebPackStream.DEFAULT_ORDER so no pack silently queues in the unknown tail.

Tests

• New tools/tests/pack_request_gate_test.gd (20 checks): pending pack demands once + no null poisoning, _warm_one yields without caching, arrival clears the wait set / drops stale nulls / the scene then loads and caches, genuine miss keeps the old completed-null behavior, no-stream desktop unchanged, teardown with a pending pack is safe, midlod demands once and the completed twin survives arrival.
• tools/gate.sh quick PASS, tools/gate.sh full PASS, pytest 96 passed (coverage 97.11%), pre-commit checks pass (API docs regenerated).

Second commit tracks the people_pool.gd.uid that #112 missed (import noise for every fresh worktree).

Co-authored-by: factory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>

[github-actions]

Automated review

No new findings on the 12 changed files (gdlint, complexity, TODO policy, dead code).

Run python3 tools/checks/run_all.py locally for the full set of checks.