test(snap): cover bare vp lint / vp fmt --check at the workspace root

Adds claim 2c/2d to probe deeper cwds where lint and fmt diverge
(lint stays on oxlint defaults from pkg-a/src, fmt walks up to
pkg-a's vite.config.ts), and replaces the targeted per-package lint
commands in claim 3 with the bare `vp lint --threads=1` / `vp fmt
--check` invocations a user would actually run. `--threads=1` keeps
the multi-error output order stable across snapshot runs.

Author: fengmk2

packages/cli/snap-tests/docs-nested-config/snap.txt

@@ -41,25 +41,36 @@ src/index.js (<variable>ms)
 Format issues found in above 1 files. Run without `--check` to fix.
 Finished in <variable>ms on 1 files using <variable> threads.
 
-> # Claim 3: from the workspace root the root config applies to every file,
-> # including files in pkg-a that have their own vite.config.ts (not merged,
-> # and not resolved per-file). Running against each package separately keeps
-> # the snap output stable regardless of oxlint's parallel scheduling.
-[1]> vp lint packages/pkg-a/src
+> # Claim 2c: `vp lint` does not walk up even when an ancestor config exists.
+> # From pkg-a/src (pkg-a has a vite.config.ts one level up) oxlint defaults still apply,
+> # proving lint resolution does not traverse parent directories.
+> cd packages/pkg-a/src && vp lint
 
-  × eslint(no-debugger): `debugger` statement is not allowed
-   ╭─[packages/pkg-a/src/index.js:2:3]
+  ⚠ eslint(no-debugger): `debugger` statement is not allowed
+   ╭─[index.js:2:3]
  1 │ function pkgA() {
  2 │   debugger;
    ·   ─────────
  3 │   return "hello from pkg-a";
    ╰────
   help: Remove the debugger statement
 
-Found 0 warnings and 1 error.
+Found 1 warning and 0 errors.
 Finished in <variable>ms on 1 file with <variable> rules using <variable> threads.
 
-[1]> vp lint packages/pkg-b/src
+> # Claim 2d: `vp fmt` walks up several levels when needed.
+> # From pkg-a/src (no config) fmt finds pkg-a/vite.config.ts -> singleQuote:false -> passes.
+> cd packages/pkg-a/src && vp fmt --check .
+Checking formatting...
+All matched files use the correct format.
+Finished in <variable>ms on 1 files using <variable> threads.
+
+> # Claim 3: running `vp lint` / `vp fmt --check` directly at the workspace root
+> # applies the root config to every file, including files in pkg-a that have
+> # their own vite.config.ts (configs are not merged and not resolved per-file).
+> # `--threads=1` is only used to keep oxlint's multi-error output order stable
+> # across snapshot runs; it does not affect resolution.
+[1]> vp lint --threads=1
 
   × eslint(no-debugger): `debugger` statement is not allowed
    ╭─[packages/pkg-b/src/index.js:2:3]
@@ -70,16 +81,25 @@ Finished in <variable>ms on 1 file with <variable> rules using <variable> thread
    ╰────
   help: Remove the debugger statement
 
-Found 0 warnings and 1 error.
-Finished in <variable>ms on 1 file with <variable> rules using <variable> threads.
+  × eslint(no-debugger): `debugger` statement is not allowed
+   ╭─[packages/pkg-a/src/index.js:2:3]
+ 1 │ function pkgA() {
+ 2 │   debugger;
+   ·   ─────────
+ 3 │   return "hello from pkg-a";
+   ╰────
+  help: Remove the debugger statement
+
+Found 0 warnings and 2 errors.
+Finished in <variable>ms on 5 files with <variable> rules using <variable> threads.
 
-[1]> vp fmt --check packages
+[1]> vp fmt --check
 Checking formatting...
 packages/pkg-a/src/index.js (<variable>ms)
 packages/pkg-b/src/index.js (<variable>ms)
 
 Format issues found in above 2 files. Run without `--check` to fix.
-Finished in <variable>ms on 5 files using <variable> threads.
+Finished in <variable>ms on 10 files using <variable> threads.
 
 > # Claim 4: `-c <path>` bypasses cwd-based resolution. The permissive config applies
 > # to every targeted file, so both debugger statements and double-quoted strings pass.

packages/cli/snap-tests/docs-nested-config/steps.json

@@ -18,13 +18,20 @@
     "# Claim 2b: `vp fmt` DOES walk up. From pkg-b (no local config) it reaches the root,",
     "# which sets singleQuote:true -> double-quoted strings fail (exit 1).",
     "cd packages/pkg-b && vp fmt --check src",
-    "# Claim 3: from the workspace root the root config applies to every file,",
-    "# including files in pkg-a that have their own vite.config.ts (not merged,",
-    "# and not resolved per-file). Running against each package separately keeps",
-    "# the snap output stable regardless of oxlint's parallel scheduling.",
-    "vp lint packages/pkg-a/src",
-    "vp lint packages/pkg-b/src",
-    "vp fmt --check packages",
+    "# Claim 2c: `vp lint` does not walk up even when an ancestor config exists.",
+    "# From pkg-a/src (pkg-a has a vite.config.ts one level up) oxlint defaults still apply,",
+    "# proving lint resolution does not traverse parent directories.",
+    "cd packages/pkg-a/src && vp lint",
+    "# Claim 2d: `vp fmt` walks up several levels when needed.",
+    "# From pkg-a/src (no config) fmt finds pkg-a/vite.config.ts -> singleQuote:false -> passes.",
+    "cd packages/pkg-a/src && vp fmt --check .",
+    "# Claim 3: running `vp lint` / `vp fmt --check` directly at the workspace root",
+    "# applies the root config to every file, including files in pkg-a that have",
+    "# their own vite.config.ts (configs are not merged and not resolved per-file).",
+    "# `--threads=1` is only used to keep oxlint's multi-error output order stable",
+    "# across snapshot runs; it does not affect resolution.",
+    "vp lint --threads=1",
+    "vp fmt --check",
     "# Claim 4: `-c <path>` bypasses cwd-based resolution. The permissive config applies",
     "# to every targeted file, so both debugger statements and double-quoted strings pass.",
     "vp lint -c vite.config.permissive.ts",