refactor(manifest): tighten ManifestPath API

- Add `parent_or_dot()` helper to replace the repeated
  `.parent().unwrap_or_else(|| Path::new("."))` idiom at three call sites.
- Add `From<ManifestPath> for PathBuf` and use it in
  `BundleFileResolver::resolve` to drop a per-resolve `PathBuf` clone.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/crates/fabro-server/src/run_manifest.rs

@@ -385,11 +385,8 @@ fn resolve_manifest_dockerfile(
         return Ok(());
     };
     let path_owned = path.clone();
-    let manifest_path = ManifestPath::from_reference(
-        config_path.parent().unwrap_or_else(|| Path::new(".")),
-        &path_owned,
-    )
-    .ok_or_else(|| anyhow!("unsupported dockerfile reference: {path_owned}"))?;
+    let manifest_path = ManifestPath::from_reference(config_path.parent_or_dot(), &path_owned)
+        .ok_or_else(|| anyhow!("unsupported dockerfile reference: {path_owned}"))?;
     let content = files
         .get(&manifest_path)
         .cloned()

lib/crates/fabro-workflow/src/file_resolver.rs

@@ -33,9 +33,10 @@ impl BundleFileResolver {
 impl FileResolver for BundleFileResolver {
     fn resolve(&self, current_dir: &Path, reference: &str) -> Option<ResolvedFile> {
         let path = ManifestPath::from_reference(current_dir, reference)?;
-        self.files.get(&path).map(|content| ResolvedFile {
-            path:    path.as_path().to_path_buf(),
-            content: content.clone(),
+        let content = self.files.get(&path)?.clone();
+        Some(ResolvedFile {
+            path: path.into(),
+            content,
         })
     }
 }

lib/crates/fabro-workflow/src/manifest_path.rs

@@ -43,6 +43,19 @@ impl ManifestPath {
     pub fn parent(&self) -> Option<&Path> {
         self.0.parent()
     }
+
+    /// Directory that contains this path, falling back to `.` when the path
+    /// has no parent component (e.g. a bare file name).
+    #[must_use]
+    pub fn parent_or_dot(&self) -> &Path {
+        self.0.parent().unwrap_or_else(|| Path::new("."))
+    }
+}
+
+impl From<ManifestPath> for PathBuf {
+    fn from(value: ManifestPath) -> Self {
+        value.0
+    }
 }
 
 impl TryFrom<String> for ManifestPath {

lib/crates/fabro-workflow/src/workflow_bundle.rs

@@ -1,5 +1,5 @@
 use std::collections::HashMap;
-use std::path::{Path, PathBuf};
+use std::path::PathBuf;
 use std::sync::Arc;
 
 use serde::{Deserialize, Serialize};
@@ -29,9 +29,7 @@ impl BundledWorkflow {
 
     #[must_use]
     pub fn current_dir(&self) -> PathBuf {
-        self.path
-            .parent()
-            .map_or_else(|| PathBuf::from("."), Path::to_path_buf)
+        self.path.parent_or_dot().to_path_buf()
     }
 }
 
@@ -55,10 +53,7 @@ impl WorkflowBundle {
         current_workflow_path: &ManifestPath,
         reference: &str,
     ) -> Option<&BundledWorkflow> {
-        let current_dir = current_workflow_path
-            .parent()
-            .unwrap_or_else(|| Path::new("."));
-        let path = ManifestPath::from_reference(current_dir, reference)?;
+        let path = ManifestPath::from_reference(current_workflow_path.parent_or_dot(), reference)?;
         self.workflows.get(&path)
     }