go: monthly quota 100% while all local stores total ~$5 of usage

Summary

Go monthly quota shows 100% (rate-limited) while the server usage API AND every
local data store on the machine total ~$5 of paid usage in the current window —
a ~$55 discrepancy with no identifiable source.

Environment

• OpenCode version: v2.0.4 (@opencode/cli, active install serving sessions).
  A legacy opencode-ai v1.18.30 binary also exists on PATH (second/older
  install); v2 is what's actively used.
• OS: Windows 11 (10.0.22631, win32 x64) + WSL2 Ubuntu (separate opencode v2
  install, same Go key)
• Terminal: xterm-256color / truecolor
• Shell: cmd.exe (Windows); bash (WSL)
• Install/channel: latest
• Active plugins: @plannotator/opencode@latest, @upstash/context7-opencode@latest

What Happened

This month I hit the Go monthly limit (100%, rate-limited, reset
2026-09-30T05:23:21Z per GET https://opencode.ai/zen/go/v1/usage) — but every
usage number I can see says I've used only a fraction of the allowance:

• Local Windows opencode.db (Aug 31 05:23 UTC → now): $4.84 total across
  opencode-go models (deepseek-flash $1.63, glm-5.3-flash $1.44, omen-alpha
  $1.04, mimo-v2.5 $0.62, hy3 $0.01), plus $0.09 on OpenRouter and $0 on free
  models.
• WSL opencode.db (same key, separate v2 install): $0.00 paid usage in the
  window — free models only.
• No deepseek-v4-pro at all since 2026-08-12. The $51.61 recorded against
  it is entirely May–Aug usage; a date-bucketed query confirms zero rows in
  the current monthly window.
• Cache reads are large (e.g. 166.4M on deepseek-flash, 35.6M on
  glm-5.3-flash) but bill in the $0.50–$1.10 range at published Go rates.

Aggregate server-billed value of everything I can account for is ~$5–8 of the
$60 monthly allowance, yet the server reports 100% and blocking. The missing
~$52 has no source in any store I can inspect: one device, one workspace, one
key across two installs.

Expected Behavior

Monthly percent should roughly match the sum of server-billed usage for the
models I actually ran (~$5–8), or the usage history should expose where the
remaining ~$52 was attributed.

Actual Behavior

Server reports 100% monthly / rate-limited despite the ~$5 of verifiable
usage above.

Additional Context

Same symptom class as #42686, #38936, #42528, #40280, #41976, #41391, #41206,
but this report has the authoritative usage-API output and full local-store
cross-checks (Windows DB + WSL DB). Willing to run any diagnostic or share
redacted account/usage history.