fix(console): preserve usage reset boundaries

[opencode-agent]

Summary

• capture one usage timestamp before updating fixed-window counters
• use that timestamp for both period bounds and persisted counter timestamps
• ignore delayed writes from older periods and prevent timestamps from moving backward

Why

A usage write can wait on the database across a weekly or monthly reset boundary. Previously, the period was selected using application time while time_*_updated was persisted with database now(). A write that selected the old period but executed after the boundary could therefore retain old usage and stamp it as current-period usage, preventing the next request from resetting the counter.

The update now treats each fixed-window write as an event at one timestamp. It adds within that event's period, resets when advancing to a new period, and ignores delayed events when a newer period is already stored.

Checks

• bun typecheck (packages/console/app)
• bun typecheck (packages/console/core)
• bun test test/subscription.test.ts (packages/console/core)
• bun x prettier --check packages/console/app/src/routes/zen/util/handler.ts
• git diff --check

The full Console app test suite has two pre-existing failures in providerUsage.test.ts: Google normalized output tokens are currently 5, while the tests expect 3. The remaining five app tests pass.

Requested by: @MrMushrooooom (Jack via Slack)

[heimoshuiyu]

LGTM