chore: split e2e tests for real-time output (#152)

## Summary

- Split `make test` so e2e tests run as a separate `go test` invocation
instead of bundled in `go test ./...`
- Unit tests still run together (fast, ~2s total)
- E2e tests run alone with a banner message before they start

## Why

`go test ./...` buffers each package's output until the package
completes. Since e2e tests take ~2 minutes (testcontainers), the
terminal shows nothing for that entire duration — it looks like the
tests are hung.

Running e2e as a separate `go test ./e2e/` invocation makes it the only
active package, so output (container startup, health checks, test
progress) streams in real time.

There's no way to disable per-package buffering in `go test` when
running multiple packages in parallel — it's intentional to prevent
interleaved output. The `-p 1` flag would work but slows down the
overall run which is why it was removed
#137. The split approach
gives real-time streaming where it matters (e2e) with no performance
cost.

## Test plan

- [x] `make test` passes (all unit + e2e tests green)
- [x] E2e output streams in real time after the banner
- [x] Unit tests still run in parallel as before

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Makefile-only change that alters test execution ordering/invocation
but not production code; main risk is accidentally excluding/duplicating
packages due to the `go list | grep -v /e2e$` filter.
> 
> **Overview**
> `make test` now runs non-e2e packages first and executes `./e2e` tests
as a separate `go test` step, with a banner printed before the e2e run
to make progress/logs visible while testcontainers start up.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
310bc74. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: tnsardesai

server/Makefile

@@ -33,10 +33,14 @@ build: | $(BIN_DIR)
 dev: build $(RECORDING_DIR)
 	OUTPUT_DIR=$(RECORDING_DIR) DISPLAY_NUM=$(DISPLAY_NUM) ./bin/api
 
+# we run the e2e tests separately so that we can see the logs from the e2e tests as they run instead of waiting for all tests to complete
 test:
 	go vet ./...
-	# E2E tests use dynamic ports via TestContainer, enabling parallel execution
-	go test -v -race ./...
+	go test -v -race $$(go list ./... | grep -v /e2e$$)
+	@echo ""
+	@echo "=== Running e2e tests (testcontainers — this may take a few minutes) ==="
+	@echo ""
+	go test -v -race ./e2e/
 
 clean:
 	@rm -rf $(BIN_DIR)