Revert: stable client connectionId (PR #401)

[dimakis]

Summary

• Reverts PR feat(transport): stable client connectionId + POST failure resilience #401 (feat(transport): stable client connectionId + POST failure resilience)
• Root cause: stable connectionId shared identity across sessions, causing cross-session event routing
• Symptoms: browser hangs (infinite periodic sync retry loop with growing missedCounts), message bleed between sessions
• Why iOS was stable: Capacitor app hasn't been rebuilt since before feat(transport): stable client connectionId + POST failure resilience #401, so it's running pre-feat(transport): stable client connectionId + POST failure resilience #401 transport code

Evidence from logs

• connection-registry retrying missed events every 5s, missedCount climbing to 48
• Single connectionId (conn-410546be...) cursor-resetting across two different sessionIds — one connection serving events for multiple sessions

Test plan

• Browser: verify sessions connect without hanging
• Browser: verify no message bleed between sessions
• iOS: confirm no regression (already on pre-feat(transport): stable client connectionId + POST failure resilience #401 code)

🤖 Generated with Claude Code

[dimakis]

Centaur Review

Found 2 issue(s).

packages/client/src/store.ts

Clean revert of PR #401 — no dangling references, no broken imports, and removed features are fully excised. Two minor gaps: stale sendError after reconnect-flush (pre-existing), and lost test coverage for SessionSseRegistry.add() reconnect behavior.

• 🔵 regressions (L375): After revert, sendError set on failed send ('Not connected…') is only cleared when a new session starts via startChat(). If the connection recovers and the queued message is flushed successfully, the stale error banner persists in the UI until the user starts another session. This was the pre-#401 behavior being restored, but worth noting as a known gap. [fixable]

server/__tests__/session-sse-registry.test.ts

Clean revert of PR #401 — no dangling references, no broken imports, and removed features are fully excised. Two minor gaps: stale sendError after reconnect-flush (pre-existing), and lost test coverage for SessionSseRegistry.add() reconnect behavior.

• 🔵 missing_tests: The entire session-sse-registry.test.ts file was deleted. It contained tests for add (closing existing streams on reconnect) and removeIfCurrent. While removeIfCurrent was removed, the add reconnect behavior (closing stale streams) is still present in the implementation and now has no dedicated test coverage. [fixable]

[dimakis]

🔵 regressions: After revert, sendError set on failed send ('Not connected…') is only cleared when a new session starts via startChat(). If the connection recovers and the queued message is flushed successfully, the stale error banner persists in the UI until the user starts another session. This was the pre-#401 behavior being restored, but worth noting as a known gap. [fixable]