storaged cap smoke — verifies ADR-002 at 300 MiB

Closes the "needs heavy integration smoke" follow-up from the
ADR-002 commit (423a381). Until now the per-prefix PUT cap was
verified only by unit tests + commits' theory; this smoke runs
the actual cap path with real bytes.

Three assertions, ~2s wall:
  1. PUT 300 MiB to _vectors/<key> → 200 (cap raised to 4 GiB
     for the vectord persistence prefix).
  2. PUT same 300 MiB to datasets/<key> → 413 (default 256 MiB
     cap still protects routine traffic).
  3. GET _vectors/<key> → sha256 round-trips (no truncation
     between cap-raise and S3 multipart streaming).

scripts/storaged_cap_smoke.sh
  Builds storaged + gateway, boots them, generates 300 MiB
  deterministic /dev/zero payload (sha stable across runs),
  runs the 3 assertions, cleans up the keys + processes via trap.

  /dev/zero generation chosen over yes/head pipe — pipefail
  catches the SIGPIPE from yes when head closes early.

just smoke-storaged-cap
  Wrapper recipe. Outside the main `just verify` chain because
  300 MiB payload generation + transfer is MB-heavy. Run after
  meaningful storaged or vectord-persistence changes.

Verified:
  bash scripts/storaged_cap_smoke.sh — 3/3 PASS · 2s wall
  just verify                         — vet + test + 9 smokes still 33s

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

justfile

@@ -59,6 +59,12 @@ smoke day:
 smoke-g2-fixtures:
     @bash scripts/g2_smoke_fixtures.sh
 
+# Storaged cap smoke — verifies ADR-002's per-prefix PUT cap at 300 MiB.
+# Outside the main chain (MB-heavy, ~5-10s wall); run after meaningful
+# storaged or vectord-persistence changes.
+smoke-storaged-cap:
+    @bash scripts/storaged_cap_smoke.sh
+
 # All 9 smokes in dependency order. Halts on first failure.
 smoke-all:
     #!/usr/bin/env bash