test(e2e): add argv step spawn mode

Replace shell string steps with structured argv format in all e2e test
fixtures. Steps now use `argv` arrays instead of shell command strings,
with optional `comment`, `envs`, and `stdin` fields:

```toml
# Simple:
steps = [["vt", "run", "build"]]

# With metadata:
steps = [{ argv = ["vt", "run", "test"], comment = "cache miss", envs = [["MY_ENV", "1"]] }]

# With stdin piping (still uses shell internally):
steps = [{ argv = ["vt", "run", "read-stdin"], stdin = "from-stdin" }]
```

This avoids shell interference with signal handling and exit codes on
Windows. The snapshot display format is preserved by reconstructing a
shell-like command line from the argv array (with shell-escape for args
containing whitespace).

Also documents Conventional Commits format for PR titles in CLAUDE.md.

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

Author: branchseer

CLAUDE.md

@@ -38,6 +38,8 @@ just doc           # Documentation generation
 
 If `gt` (Graphite CLI) is available in PATH, use it instead of `gh` to create pull requests.
 
+PR titles must use [Conventional Commits](https://www.conventionalcommits.org) format: `type(scope): summary` (scope is optional), e.g. `feat(cache): add LRU eviction`, `fix: handle symlink loops`, `test(e2e): add ctrl-c propagation test`.
+
 ## Tests
 
 ```bash

Cargo.lock

@@ -36,8 +36,10 @@ pty_terminal = { workspace = true }
 pty_terminal_test = { workspace = true }
 regex = { workspace = true }
 serde = { workspace = true, features = ["derive", "rc"] }
+shell-escape = { workspace = true }
 tempfile = { workspace = true }
 toml = { workspace = true }
+vec1 = { workspace = true, features = ["serde"] }
 vite_path = { workspace = true, features = ["absolute-redaction"] }
 vite_workspace = { workspace = true }
 

crates/vite_task_bin/Cargo.toml

@@ -3,8 +3,26 @@
 [[e2e]]
 name = "associate existing cache"
 steps = [
-  "vt run script1 # cache miss",
-  "vt run script2 # cache hit, same command as script1",
-  "vtt replace-file-content package.json '\"script2\": \"vtt print hello\"' '\"script2\": \"vtt print world\"' # change script2",
-  "vt run script2 # cache miss",
+  { argv = [
+    "vt",
+    "run",
+    "script1",
+  ], comment = "cache miss" },
+  { argv = [
+    "vt",
+    "run",
+    "script2",
+  ], comment = "cache hit, same command as script1" },
+  { argv = [
+    "vtt",
+    "replace-file-content",
+    "package.json",
+    "\"script2\": \"vtt print hello\"",
+    "\"script2\": \"vtt print world\"",
+  ], comment = "change script2" },
+  { argv = [
+    "vt",
+    "run",
+    "script2",
+  ], comment = "cache miss" },
 ]

crates/vite_task_bin/tests/e2e_snapshots/fixtures/associate-existing-cache/snapshots.toml

@@ -3,8 +3,24 @@
 [[e2e]]
 name = "builtin different cwd"
 steps = [
-  "vt run cwd1 # cache miss in folder1",
-  "vt run cwd2 # cache miss in folder2 (different cwd)",
-  "vt run cwd1 # cache hit in folder1",
-  "vt run cwd2 # cache hit in folder2",
+  { argv = [
+    "vt",
+    "run",
+    "cwd1",
+  ], comment = "cache miss in folder1" },
+  { argv = [
+    "vt",
+    "run",
+    "cwd2",
+  ], comment = "cache miss in folder2 (different cwd)" },
+  { argv = [
+    "vt",
+    "run",
+    "cwd1",
+  ], comment = "cache hit in folder1" },
+  { argv = [
+    "vt",
+    "run",
+    "cwd2",
+  ], comment = "cache hit in folder2" },
 ]

crates/vite_task_bin/tests/e2e_snapshots/fixtures/builtin-different-cwd/snapshots.toml

@@ -2,8 +2,30 @@
 
 [[e2e]]
 name = "task with cache disabled"
-steps = ["vt run no-cache-task # cache miss", "vt run no-cache-task # cache disabled, runs again"]
+steps = [
+  { argv = [
+    "vt",
+    "run",
+    "no-cache-task",
+  ], comment = "cache miss" },
+  { argv = [
+    "vt",
+    "run",
+    "no-cache-task",
+  ], comment = "cache disabled, runs again" },
+]
 
 [[e2e]]
 name = "task with cache enabled"
-steps = ["vt run cached-task # cache miss", "vt run cached-task # cache hit"]
+steps = [
+  { argv = [
+    "vt",
+    "run",
+    "cached-task",
+  ], comment = "cache miss" },
+  { argv = [
+    "vt",
+    "run",
+    "cached-task",
+  ], comment = "cache hit" },
+]

crates/vite_task_bin/tests/e2e_snapshots/fixtures/cache-disabled/snapshots.toml

@@ -3,9 +3,33 @@
 [[e2e]]
 name = "cache miss command change"
 steps = [
-  "vt run task # cache miss",
-  "vtt replace-file-content vite-task.json 'vtt print foo && vtt print bar' 'vtt print baz && vtt print bar' # change first subtask",
-  "vt run task # first: cache miss, second: cache hit",
-  "vtt replace-file-content vite-task.json 'vtt print baz && vtt print bar' 'vtt print bar' # remove first subtask",
-  "vt run task # cache hit",
+  { argv = [
+    "vt",
+    "run",
+    "task",
+  ], comment = "cache miss" },
+  { argv = [
+    "vtt",
+    "replace-file-content",
+    "vite-task.json",
+    "vtt print foo && vtt print bar",
+    "vtt print baz && vtt print bar",
+  ], comment = "change first subtask" },
+  { argv = [
+    "vt",
+    "run",
+    "task",
+  ], comment = "first: cache miss, second: cache hit" },
+  { argv = [
+    "vtt",
+    "replace-file-content",
+    "vite-task.json",
+    "vtt print baz && vtt print bar",
+    "vtt print bar",
+  ], comment = "remove first subtask" },
+  { argv = [
+    "vt",
+    "run",
+    "task",
+  ], comment = "cache hit" },
 ]