Use EACL for the recursive user directory demo

[theronic]

What changed

• remove the Explorer-only indexed user directory and enumerate users through EACL lookup-subjects
• compute the displayed total through EACL count-subjects; no user-directory result or count is taken from seed metadata
• propagate the Cache toggle to both directory queries, so disabled and enabled timings measure the actual EACL path
• paginate users with the v8 opaque Relay cursors instead of numeric offsets
• add a hidden platform authorization resource that registers every seeded user
• add recursive nested-team inheritance (parent->admin) and seed deterministic parent chains so server visibility exercises recursive schema
• pin EACL and EACL DataScript to Cache recursive plans and bound page prefetch eacl#100
• update browser tests and the query benchmark to cover the EACL-backed directory and recursive grants

Demo behavior

The platform resource is an authorization/indexing root and is hidden from the normal resource columns. Teams form bounded parent chains within each account. A leader of an earlier team inherits admin over later child teams, and server/view reaches that grant through team->view.

The directory latency now covers both the page lookup and exact EACL count. It does not time React rendering or seed metadata.

Validation

• Shadow app and test builds: 0 warnings
• browser CLJS suite: 45 tests, 219 assertions, 0 failures/errors
• live smoke seed: 10,000 servers, 38 users; opaque next/previous user cursors work
• 10k recursive benchmark, 20-result server page: uncached 3.255 ms mean / 3.200 ms p50; cached 0.146 ms mean
• 10k full user-directory workload (page plus count): uncached 2.611 ms mean / 2.600 ms p50; cached 0.156 ms mean

Parent PR: #2
Engine optimization: theronic/eacl#100

[theronic]

Final browser measurements with the directory fully EACL-backed (both lookup-subjects and count-subjects are timed; no seed-metadata total):

10k-server workload	cache disabled	cache enabled
recursive server page, 20 results	3.255 ms mean / 3.200 ms p50	0.146 ms mean
user directory page + exact count	2.611 ms mean / 2.600 ms p50	0.156 ms mean

The Cache toggle is passed to both directory queries. Browser suite: 45 tests / 219 assertions, all green.