Pnpm's workspace-manifest-reader (workspace/workspace-manifest-reader/
src/index.ts at 8eb1be4988) treats only `ENOENT` as "no manifest" —
every other error (read failure, invalid yaml) fails the process.
Pacquet was silently swallowing all errors via `if let Ok(Some(...))`,
which left typos in `pnpm-workspace.yaml` undetected and silently
fell back to `.npmrc`/defaults, diverging from pnpm 11.

Make `Npmrc::current` fallible. `find_and_load` already returns
`Ok(None)` for the missing-file case (file presence is gated by
`is_file()`); read/parse errors now bubble up wrapped in a new
`LoadWorkspaceYamlError` that carries the offending path and
implements `miette::Diagnostic` so the CLI prints a clean message.
The variants box their inner payloads to keep the result small.

Update the CLI call sites and add a test that asserts invalid yaml
surfaces as `ParseYaml` instead of being silently dropped.

Resolves #402.

---
Written by an agent (Claude Code, claude-opus-4-7).

Apply CONTRIBUTING.md's writing-style guidance to the doc comments and
inline comments added in 7077200: drop em dashes, restructure
sentences so each clause stands alone, and shorten paragraphs that
restated information already obvious from the surrounding code.

https://claude.ai/code/session_015KiPxroFpb2pgBa92YeJM1

`LoadWorkspaceYamlError::ParseYaml` is a tuple variant. Using the
tuple-form `ParseYaml(_)` rather than `ParseYaml { .. }` matches
Rust convention for tuple variants. The struct-form pattern compiles
and the test passes either way.

https://claude.ai/code/session_015KiPxroFpb2pgBa92YeJM1

The previous shape wrapped every variant in a payload struct
(`ReadFileError`, `ParseYamlError`) whose own `Display` repeated
`{path}: {error}`. Rendered through miette this surfaced the path
twice — once in the variant's main message, once in the `Caused by:`
chain.

Drop the payload structs and store `path` + `source` directly on the
struct variants, mirroring `pacquet_modules_yaml::ReadModulesError`.
Only `serde_saphyr::Error` is large enough to need boxing; `io::Error`
fits the variant inline. The diagnostic now reads cleanly:

    Failed to parse pnpm-workspace.yaml at /…/pnpm-workspace.yaml: <yaml error>
      Caused by: <yaml error>

instead of repeating the path in the `Caused by:` line.

The test pattern moves back to struct-variant form
(`ParseYaml { .. }`) to match.

https://claude.ai/code/session_015KiPxroFpb2pgBa92YeJM1

`find_and_load` previously routed candidate paths through
`find_workspace_manifest`, which gated each level on `is_file()` and
walked up otherwise. That filter swallowed cases where the entry
existed but was not a regular file (most notably a directory named
`pnpm-workspace.yaml`), so the stated "only `ENOENT` is silent"
contract — the one pnpm's `readManifestRaw` actually delivers — did
not hold.

Replace the find-then-read split with a single read-and-catch loop
over `start_dir.ancestors()`: at each level read
`pnpm-workspace.yaml`, treat `ErrorKind::NotFound` as "no manifest
here, walk up", and propagate every other error (`EISDIR`, permission
denied, etc.) through the existing `LoadWorkspaceYamlError`
variants. This also closes the TOCTOU window between the old
`is_file()` check and the read.

The private `find_workspace_manifest` helper stays in place because
`workspace_root_or` still uses it; only `find_and_load` switches to
the new shape.

Add a test that creates a directory named `pnpm-workspace.yaml` and
asserts the result is `Err(ReadFile { .. })` rather than the previous
silent `Ok(None)`.

https://claude.ai/code/session_015KiPxroFpb2pgBa92YeJM1