fix(realtime): include join_ref on every client-sent channel event

[grdsdev]

AsyncPush.send() built outgoing Messages with only ref, leaving join_ref permanently null. The Realtime protocol requires join_ref on every client-sent event (join, leave, broadcast, presence track/untrack) so the server can detect stale messages after a rejoin; newer Phoenix versions rely on it and silently drop pushes that omit it — this matches the track/untrack timeout reports that motivated this check.

Fix: AsyncPush.send() now sets join_ref=self.channel.join_push.ref when building the outgoing message.

Test plan

• Added tests/test_join_ref.py (5 tests): join carries join_ref == ref, broadcast/track/untrack carry the channel's join_ref, leave carries the pre-leave join_ref, rejoin produces a fresh join_ref.
• ruff check / ruff format --check: clean.
• mypy src/realtime tests: clean.
• pytest tests/: 25 passed, 6 failed — the 6 failures need a local Supabase stack (127.0.0.1:54321) and fail identically on main, unrelated to this change.

Fixes SDK-1526

[github-actions]

⚠️ Capability matrix drift detected

The following capabilities are marked implemented in the matrix but could not be found in python:

• database.configuration.auto_retry → expected symbol: AsyncSelectRequestBuilder.retry
• database.configuration.auto_retry → expected symbol: SyncSelectRequestBuilder.retry
• realtime.client.connect → expected symbol: SyncRealtimeClient.connect
• realtime.client.disconnect → expected symbol: AsyncRealtimeClient.disconnect
• realtime.client.disconnect → expected symbol: SyncRealtimeClient.disconnect
• realtime.channel.subscribe → expected symbol: SyncRealtimeChannel.subscribe
• realtime.channel.unsubscribe → expected symbol: SyncRealtimeChannel.unsubscribe
• realtime.channel.broadcast → expected symbol: SyncRealtimeChannel.send_broadcast
• realtime.subscriptions.broadcast → expected symbol: SyncRealtimeChannel.on_broadcast
• realtime.subscriptions.postgres_changes → expected symbol: SyncRealtimeChannel.on_postgres_changes
• realtime.subscriptions.subscribe_presence → expected symbol: AsyncRealtimeChannel.on_presence_change
• realtime.subscriptions.subscribe_presence → expected symbol: SyncRealtimeChannel.on_presence_change
• realtime.presence.track → expected symbol: SyncRealtimeChannel.track
• realtime.presence.untrack → expected symbol: SyncRealtimeChannel.untrack
• realtime.presence.presence_state → expected symbol: AsyncRealtimeChannel.presences
• realtime.presence.presence_state → expected symbol: SyncRealtimeChannel.presences

The following capabilities are marked implemented in python but have no registered symbols to verify:

• auth.session.auto_refresh (no symbols list — cannot confirm implementation exists)
• client.authentication_integration.cross_client_token_sync (no symbols list — cannot confirm implementation exists)
• client.authentication_integration.oauth_flow_type (no symbols list — cannot confirm implementation exists)
• client.session_management.custom_storage (no symbols list — cannot confirm implementation exists)
• client.session_management.persist_session (no symbols list — cannot confirm implementation exists)
• client.request_configuration.custom_http_client (no symbols list — cannot confirm implementation exists)
• client.request_configuration.global_headers (no symbols list — cannot confirm implementation exists)
• database.mutate.select_after_mutation (no symbols list — cannot confirm implementation exists)
• database.using_filters.eq (no symbols list — cannot confirm implementation exists)
• database.using_filters.neq (no symbols list — cannot confirm implementation exists)
• database.using_filters.gt (no symbols list — cannot confirm implementation exists)
• database.using_filters.gte (no symbols list — cannot confirm implementation exists)
• database.using_filters.lt (no symbols list — cannot confirm implementation exists)
• database.using_filters.lte (no symbols list — cannot confirm implementation exists)
• database.using_filters.like (no symbols list — cannot confirm implementation exists)
• database.using_filters.ilike (no symbols list — cannot confirm implementation exists)
• database.using_filters.is (no symbols list — cannot confirm implementation exists)
• database.using_filters.in (no symbols list — cannot confirm implementation exists)
• database.using_filters.contains (no symbols list — cannot confirm implementation exists)
• database.using_filters.contained_by (no symbols list — cannot confirm implementation exists)
• database.using_filters.range_gt (no symbols list — cannot confirm implementation exists)
• database.using_filters.range_gte (no symbols list — cannot confirm implementation exists)
• database.using_filters.range_lt (no symbols list — cannot confirm implementation exists)
• database.using_filters.range_lte (no symbols list — cannot confirm implementation exists)
• database.using_filters.range_adjacent (no symbols list — cannot confirm implementation exists)
• database.using_filters.overlaps (no symbols list — cannot confirm implementation exists)
• database.using_filters.text_search (no symbols list — cannot confirm implementation exists)
• database.using_filters.match (no symbols list — cannot confirm implementation exists)
• database.using_filters.not (no symbols list — cannot confirm implementation exists)
• database.using_filters.or (no symbols list — cannot confirm implementation exists)
• database.using_filters.raw (no symbols list — cannot confirm implementation exists)
• database.using_filters.regex (no symbols list — cannot confirm implementation exists)
• database.using_filters.regex_icase (no symbols list — cannot confirm implementation exists)
• database.using_filters.not_in (no symbols list — cannot confirm implementation exists)
• database.using_modifiers.order (no symbols list — cannot confirm implementation exists)
• database.using_modifiers.limit (no symbols list — cannot confirm implementation exists)
• database.using_modifiers.range (no symbols list — cannot confirm implementation exists)
• database.using_modifiers.request_cancellation (no symbols list — cannot confirm implementation exists)
• database.using_modifiers.relationship_embed (no symbols list — cannot confirm implementation exists)
• database.configuration.request_timeout (no symbols list — cannot confirm implementation exists)
• functions.invocation.region_selection (no symbols list — cannot confirm implementation exists)
• functions.invocation.request_cancellation (no symbols list — cannot confirm implementation exists)
• functions.invocation.timeout (no symbols list — cannot confirm implementation exists)
• realtime.subscriptions.postgres_changes_filter (no symbols list — cannot confirm implementation exists)
• realtime.subscriptions.private_channel (no symbols list — cannot confirm implementation exists)
• realtime.subscriptions.broadcast_self (no symbols list — cannot confirm implementation exists)
• realtime.subscriptions.broadcast_replay (no symbols list — cannot confirm implementation exists)
• realtime.presence.presence_key (no symbols list — cannot confirm implementation exists)
• realtime.configuration.heartbeat_interval (no symbols list — cannot confirm implementation exists)
• storage.file_buckets.access_bucket (no symbols list — cannot confirm implementation exists)

These may have been renamed, removed, or never registered. Please update the capability matrix.
See: https://github.com/supabase/sdk/blob/main/packages/capability-matrix/docs/capability-matrix.md