Fix signup count descriptions incorrectly including withdrawn/waitlisted signups

[nbudin]

Purpose

Fixes #8468 (and a family of related reports going back years). When a player withdrew from an event, the notification email sent to GMs reported the wrong waitlist/signup counts.

The root cause was in SignupCountPresenter#bucket_descriptions: it was summing counts without a state: filter, so withdrawn signups could bleed into the displayed totals depending on their remaining attributes. The fix is to always pass the relevant state: through to count_data.count.

While investigating, I also found a pre-existing bug where waitlisted signups always showed a count of 0 in the description text (even though waitlist_count itself was correct). Waitlisted signups have bucket_key: nil, so filtering by bucket_key: some_key never matched them. For single-bucket events this is fixed by dropping the unnecessary bucket filter; for multi-bucket events it's fixed by filtering on requested_bucket_key (where the waitlist preference actually lives) instead of bucket_key.

Changes

• bucket_descriptions now passes state: to all count_data.count calls, preventing withdrawn signups from inflating totals
• Single-bucket waitlisted: counts all waitlisted signups rather than filtering by bucket_key (which waitlisted signups never have)
• Multi-bucket waitlisted: filters by requested_bucket_key instead of bucket_key for per-bucket breakdown
• Extracted single_bucket_descriptions, multi_bucket_descriptions, and per_bucket_description private helpers to keep bucket_descriptions within complexity limits
• Added SignupCountPresenterTest with 13 tests covering the fixed behavior

Testing

The new test suite covers confirmed counts, waitlist counts, has_waitlist?, and signups_description output for both single- and multi-bucket events, with explicit cases verifying withdrawn signups are excluded.

🤖 Generated with Claude Code

[github-actions]

Code Coverage Report: Only Changed Files listed

Package	Base Coverage	New Coverage	Difference
app/presenters/signup_count_presenter.rb	🟢 89.52%	🟢 91.07%	🟢 1.55%
test/presenters/signup_count_presenter_test.rb	🔴 0%	🟢 100%	🟢 100%
Overall Coverage	🟢 53.79%	🟢 53.91%	🟢 0.12%

Minimum allowed coverage is 0%, this run produced 53.91%