Restructure integration-test just targets

`just e2e` was the visible-UI runner, but it's only useful for a single test
(and even then only with --sandbox/--slow); running it without arguments is far
too slow, yet it was easy to invoke by reflex when `just e2e-all` (run all
headlessly) was meant.

Make `just e2e` the everyday headless runner: no arguments runs the whole
suite (what e2e-all did), and a test name runs just that one headlessly via
`go test -run` — which we had no target for before. The visible-UI runner moves
to `e2e-cli`, pairing with the existing `e2e-tui` (the two main.go subcommands).
e2e-all is now redundant and removed.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

AGENTS.md

@@ -21,8 +21,9 @@ Windows box has only `just`).
 - `just format` — `gofumpt -l -w .`. Run before every commit.
 - `just build` — build the binary.
 - `just unit-test` — `go test ./... -short`.
-- `just e2e-all` — run all integration tests headlessly (`just e2e <name>` runs a
-  single one with a visible UI).
+- `just e2e` — run all integration tests headlessly; `just e2e <name>` runs a
+  single one headlessly too. `just e2e-cli <name>` runs one with a visible UI
+  (most useful with `--sandbox` or `--slow`).
 - `just lint` — run golangci-lint.
 
 ## When to commit

justfile

@@ -23,7 +23,7 @@ unit-test:
 
 # Run both unit tests and integration tests.
 [unix]
-test: unit-test e2e-all
+test: unit-test e2e
 
 # On Windows, integration tests are not supported right now
 [windows]
@@ -39,18 +39,29 @@ format:
 lint:
     ./scripts/golangci-lint-shim.sh run
 
-# Run integration tests with a visible UI. Most useful for running a single test; for running all tests, use `e2e-all` instead.
+e2e-test-command := "go test pkg/integration/clients/*.go"
+
+# Run integration tests headlessly: no args runs all tests, a test name (or path) runs just that one. Use e2e-cli for a visible UI.
 e2e *args:
+    {{ if args == "" { e2e-test-command } else { \
+        e2e-test-command + " -run 'TestIntegration/" + \
+        replace( \
+            replace_regex( \
+                replace_regex(args, '\S*pkg/integration/tests/', ''), \
+                '\.go( |$)', '${1}' \
+            ), \
+            " ", "$' && " + e2e-test-command + " -run 'TestIntegration/" \
+        ) + "$'" \
+    } }}
+
+# Run a single integration test with a visible UI; most useful with --sandbox or --slow.
+e2e-cli *args:
     go run cmd/integration_test/main.go cli {{ args }}
 
 # Open the TUI for running integration tests.
 e2e-tui *args:
     go run cmd/integration_test/main.go tui {{ args }}
 
-# Run all integration tests headlessly (without a visible UI).
-e2e-all:
-    go test pkg/integration/clients/*.go
-
 # Run some tests on the current commit, similar to what CI does.
 check:
     ./scripts/check_commit.sh