test: replace stdio e2e tests with per-mode coverage

Remove stdio-detection, stdin-inheritance, and stdio-graph-criteria
fixtures. Replace with interleaved-stdio, labeled-stdio, and
grouped-stdio fixtures that systematically cover all stdio cases
for each --log mode.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: branchseer

crates/vite_task_bin/tests/e2e_snapshots/fixtures/grouped-stdio/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "grouped-stdio-test",
+  "private": true
+}

…-inheritance/packages/other/package.json …rouped-stdio/packages/other/package.jsoncrates/vite_task_bin/tests/e2e_snapshots/fixtures/stdin-inheritance/packages/other/package.json renamed to crates/vite_task_bin/tests/e2e_snapshots/fixtures/grouped-stdio/packages/other/package.json crates/vite_task_bin/tests/e2e_snapshots/fixtures/stdin-inheritance/packages/other/package.json renamed to crates/vite_task_bin/tests/e2e_snapshots/fixtures/grouped-stdio/packages/other/package.json

@@ -1,6 +1,8 @@
 {
   "name": "other",
   "scripts": {
+    "check-tty": "check-tty",
+    "check-tty-cached": "check-tty",
     "read-stdin": "read-stdin"
   }
 }

crates/vite_task_bin/tests/e2e_snapshots/fixtures/grouped-stdio/pnpm-workspace.yaml

@@ -0,0 +1,2 @@
+packages:
+  - 'packages/*'

crates/vite_task_bin/tests/e2e_snapshots/fixtures/grouped-stdio/snapshots.toml

@@ -0,0 +1,42 @@
+# Tests stdio behavior in grouped mode (--log=grouped).
+#
+# In grouped mode, stdio is always piped regardless of cache state:
+# - stdin is /dev/null
+# - stdout/stderr are buffered per task and printed as a block on completion
+#
+# `check-tty` prints whether each stdio fd is a TTY.
+# `read-stdin` reads one line from stdin and prints it.
+
+# ─── stdout/stderr: always piped (not-tty), output grouped ───
+
+[[e2e]]
+name = "single task, cache off, grouped output"
+steps = ["vt run --log=grouped check-tty"]
+
+[[e2e]]
+name = "multiple tasks, cache off, grouped output"
+steps = ["vt run --log=grouped -r check-tty"]
+
+[[e2e]]
+name = "single task, cache miss, grouped output"
+steps = ["vt run --log=grouped check-tty-cached"]
+
+[[e2e]]
+name = "multiple tasks, cache miss, grouped output"
+steps = ["vt run --log=grouped -r check-tty-cached"]
+
+# ─── cache hit → replayed in grouped blocks ───────────────────
+
+[[e2e]]
+name = "single task, cache hit, replayed"
+steps = ["vt run --log=grouped check-tty-cached", "vt run --log=grouped check-tty-cached"]
+
+[[e2e]]
+name = "multiple tasks, cache hit, replayed"
+steps = ["vt run --log=grouped -r check-tty-cached", "vt run --log=grouped -r check-tty-cached"]
+
+# ─── stdin: always null ───────────────────────────────────────
+
+[[e2e]]
+name = "stdin is always null"
+steps = ["echo from-stdin | vt run --log=grouped read-stdin"]

crates/vite_task_bin/tests/e2e_snapshots/fixtures/grouped-stdio/snapshots/multiple tasks, cache hit, replayed.snap

@@ -0,0 +1,34 @@
+---
+source: crates/vite_task_bin/tests/e2e_snapshots/main.rs
+expression: e2e_outputs
+---
+> vt run --log=grouped -r check-tty-cached
+[other#check-tty-cached] ~/packages/other$ check-tty
+── [other#check-tty-cached] ──
+stdin:not-tty
+stdout:not-tty
+stderr:not-tty
+
+[grouped-stdio-test#check-tty-cached] $ check-tty
+── [grouped-stdio-test#check-tty-cached] ──
+stdin:not-tty
+stdout:not-tty
+stderr:not-tty
+
+---
+vt run: 0/2 cache hit (0%). (Run `vt run --last-details` for full details)
+> vt run --log=grouped -r check-tty-cached
+[other#check-tty-cached] ~/packages/other$ check-tty ◉ cache hit, replaying
+── [other#check-tty-cached] ──
+stdin:not-tty
+stdout:not-tty
+stderr:not-tty
+
+[grouped-stdio-test#check-tty-cached] $ check-tty ◉ cache hit, replaying
+── [grouped-stdio-test#check-tty-cached] ──
+stdin:not-tty
+stdout:not-tty
+stderr:not-tty
+
+---
+vt run: 2/2 cache hit (100%), <duration> saved. (Run `vt run --last-details` for full details)

crates/vite_task_bin/tests/e2e_snapshots/fixtures/grouped-stdio/snapshots/multiple tasks, cache miss, grouped output.snap

@@ -0,0 +1,19 @@
+---
+source: crates/vite_task_bin/tests/e2e_snapshots/main.rs
+expression: e2e_outputs
+---
+> vt run --log=grouped -r check-tty-cached
+[other#check-tty-cached] ~/packages/other$ check-tty
+── [other#check-tty-cached] ──
+stdin:not-tty
+stdout:not-tty
+stderr:not-tty
+
+[grouped-stdio-test#check-tty-cached] $ check-tty
+── [grouped-stdio-test#check-tty-cached] ──
+stdin:not-tty
+stdout:not-tty
+stderr:not-tty
+
+---
+vt run: 0/2 cache hit (0%). (Run `vt run --last-details` for full details)

… piped for nested single-node graph.snap …le tasks, cache off, grouped output.snapcrates/vite_task_bin/tests/e2e_snapshots/fixtures/stdio-graph-criteria/snapshots/multi-node ancestor forces piped for nested single-node graph.snap renamed to crates/vite_task_bin/tests/e2e_snapshots/fixtures/grouped-stdio/snapshots/multiple tasks, cache off, grouped output.snap crates/vite_task_bin/tests/e2e_snapshots/fixtures/stdio-graph-criteria/snapshots/multi-node ancestor forces piped for nested single-node graph.snap renamed to crates/vite_task_bin/tests/e2e_snapshots/fixtures/grouped-stdio/snapshots/multiple tasks, cache off, grouped output.snap

@@ -2,13 +2,15 @@
 source: crates/vite_task_bin/tests/e2e_snapshots/main.rs
 expression: e2e_outputs
 ---
-> vt run -r foo-nested
-~/packages/other$ check-tty ⊘ cache disabled
+> vt run --log=grouped -r check-tty
+[other#check-tty] ~/packages/other$ check-tty
+── [other#check-tty] ──
 stdin:not-tty
 stdout:not-tty
 stderr:not-tty
 
-$ check-tty ⊘ cache disabled
+[grouped-stdio-test#check-tty] $ check-tty ⊘ cache disabled
+── [grouped-stdio-test#check-tty] ──
 stdin:not-tty
 stdout:not-tty
 stderr:not-tty

crates/vite_task_bin/tests/e2e_snapshots/fixtures/grouped-stdio/snapshots/single task, cache hit, replayed.snap

@@ -0,0 +1,19 @@
+---
+source: crates/vite_task_bin/tests/e2e_snapshots/main.rs
+expression: e2e_outputs
+---
+> vt run --log=grouped check-tty-cached
+[grouped-stdio-test#check-tty-cached] $ check-tty
+── [grouped-stdio-test#check-tty-cached] ──
+stdin:not-tty
+stdout:not-tty
+stderr:not-tty
+> vt run --log=grouped check-tty-cached
+[grouped-stdio-test#check-tty-cached] $ check-tty ◉ cache hit, replaying
+── [grouped-stdio-test#check-tty-cached] ──
+stdin:not-tty
+stdout:not-tty
+stderr:not-tty
+
+---
+vt run: cache hit, <duration> saved.

crates/vite_task_bin/tests/e2e_snapshots/fixtures/grouped-stdio/snapshots/single task, cache miss, grouped output.snap

@@ -0,0 +1,10 @@
+---
+source: crates/vite_task_bin/tests/e2e_snapshots/main.rs
+expression: e2e_outputs
+---
+> vt run --log=grouped check-tty-cached
+[grouped-stdio-test#check-tty-cached] $ check-tty
+── [grouped-stdio-test#check-tty-cached] ──
+stdin:not-tty
+stdout:not-tty
+stderr:not-tty

crates/vite_task_bin/tests/e2e_snapshots/fixtures/grouped-stdio/snapshots/single task, cache off, grouped output.snap

@@ -0,0 +1,10 @@
+---
+source: crates/vite_task_bin/tests/e2e_snapshots/main.rs
+expression: e2e_outputs
+---
+> vt run --log=grouped check-tty
+[grouped-stdio-test#check-tty] $ check-tty ⊘ cache disabled
+── [grouped-stdio-test#check-tty] ──
+stdin:not-tty
+stdout:not-tty
+stderr:not-tty