feat(server): narrow event subscriptions by session interest

[armancharan]

Issue for this PR

Closes #36443

#36443

Parent: #36441

✧ raised · ○ in review · ● approved · ✓ merged

#36441 epic: scope streams + bound payloads

Merge in order:
v2
└ ○ #37486 location interest
   └ ○ #37487 session interest + fan-out bench ← this PR
      └ ○ #37585 stream ownership / diagnostics
         └ ○ #37586 reconnect herd

Siblings under the epic (not git parents of the stack tip):
└ ○ #37559 session blobs + payloadHash
└ ○ #37570 ensure-on-first-failure → feeds #37586

Stacked on #37486. Merge that first, or take both together. Includes the non-gating fan-out benchmark Kit asked for on #36441 / #36443.

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Adds optional session interest on top of location scoping. Repeated session query params narrow delivery for events that carry a session identity (Event.sessionIDOf: durable aggregate ID or data.sessionID). Location-scoped events without a session still deliver. TUI reconnects the stream when the active session family changes.

Includes the 11-client fan-out regression that encodes once per event while offering only to interested subscribers. Location interest requires location[directory]; workspace-only queries are rejected.

How did you verify your code works?

• packages/server test/event-feed.test.ts — location/session filter, encode-once, 11-client fan-out, workspace-without-directory rejected, global types bypass
• packages/server test/event-feed-fanout.bench.test.ts — clients 1..16 × small/medium/large; encode-once and bytes independent of uninterested N (timings/RSS logged, non-gating)
• packages/schema test/event.test.ts — sessionIDOf
• packages/tui test/context/client-interest.test.ts — subscribeInput / interestEqual
• packages/tui test/cli/tui/client-scope.test.tsx — event.scope reconnects on interest change only
• typecheck for schema, protocol, server, client, tui

Acceptance → test

• Fan-out cost ∝ interested subscribers (encode-once; bytes scale with payload, not N) → accounting laws hold across client counts and payload sizes

• Session A does not receive session B → delivers session-scoped events only to interested subscribers

• Location-only events still flow under session interest → keeps location-only events flowing when session interest is set

• Encode once for interested N → fans out eleven concurrent clients by interest, encoding once per event / encodes once for multiple scoped subscribers…

• Workspace without directory rejected → rejects workspace interest without a directory

• TUI reconnect on interest change → client-scope + client-interest tests above

Screenshots / recordings

N/A — not a UI layout change.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Based on my search, I found one related PR:

Related PR:

• feat(server): opt-in location interest for event subscriptions #37486 - feat(server): opt-in location interest for event subscriptions
  • This PR is the parent/dependency mentioned in the current PR (feat(server): narrow event subscriptions by session interest #37487). The current PR explicitly states: "Stacked on feat(server): opt-in location interest for event subscriptions #37486 (location interest). Merge that first, or take both together."

The current PR (#37487) builds on top of #37486 by adding session-level filtering on top of the location scoping that #37486 introduces. They are designed to be applied together as a stacked change.

No duplicate PRs found - the search shows only these two related PRs which are intentionally complementary features in a stack.