Clean up fabro-validate extraction

- Add From<ValidationError> for FabroError to eliminate duplicated
  .map_err(|e| FabroError::Validation(e.0)) at call sites
- Use top-level `use` imports for stylesheet types in rules.rs
  instead of verbose fully-qualified paths
- Remove duplicate parse_condition tests from fabro-workflows
  (already covered by fabro-graphviz)
- Use //! inner doc comments in context/keys.rs

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

lib/crates/fabro-validate/src/rules.rs

@@ -3,6 +3,7 @@ use std::str::FromStr;
 
 use fabro_graphviz::condition::parse_condition;
 use fabro_graphviz::graph::{is_llm_handler_type, AttrValue, Graph};
+use fabro_graphviz::stylesheet::{parse_stylesheet, Selector};
 
 use crate::{Diagnostic, LintRule, Severity};
 
@@ -348,7 +349,7 @@ impl LintRule for StylesheetSyntaxRule {
         if stylesheet.is_empty() {
             return Vec::new();
         }
-        match fabro_graphviz::stylesheet::parse_stylesheet(stylesheet) {
+        match parse_stylesheet(stylesheet) {
             Ok(_) => Vec::new(),
             Err(e) => vec![Diagnostic {
                 rule: self.name().to_string(),
@@ -902,12 +903,12 @@ impl LintRule for ScriptAbsoluteCdRule {
 struct StylesheetModelKnownRule;
 
 impl StylesheetModelKnownRule {
-    fn selector_label(selector: &fabro_graphviz::stylesheet::Selector) -> String {
+    fn selector_label(selector: &Selector) -> String {
         match selector {
-            fabro_graphviz::stylesheet::Selector::Universal => "*".to_string(),
-            fabro_graphviz::stylesheet::Selector::Shape(s) => s.clone(),
-            fabro_graphviz::stylesheet::Selector::Class(c) => format!(".{c}"),
-            fabro_graphviz::stylesheet::Selector::Id(id) => format!("#{id}"),
+            Selector::Universal => "*".to_string(),
+            Selector::Shape(s) => s.clone(),
+            Selector::Class(c) => format!(".{c}"),
+            Selector::Id(id) => format!("#{id}"),
         }
     }
 }
@@ -922,7 +923,7 @@ impl LintRule for StylesheetModelKnownRule {
         if stylesheet_str.is_empty() {
             return Vec::new();
         }
-        let stylesheet = match fabro_graphviz::stylesheet::parse_stylesheet(stylesheet_str) {
+        let stylesheet = match parse_stylesheet(stylesheet_str) {
             Ok(ss) => ss,
             Err(_) => return Vec::new(), // syntax errors caught by stylesheet_syntax rule
         };

lib/crates/fabro-workflows/src/condition.rs

@@ -261,18 +261,6 @@ mod tests {
         ));
     }
 
-    #[test]
-    fn parse_condition_validates() {
-        assert!(parse_condition("outcome=success").is_ok());
-        assert!(parse_condition("outcome=success && context.x=y").is_ok());
-        assert!(parse_condition("").is_ok());
-    }
-
-    #[test]
-    fn parse_condition_accepts_bare_key() {
-        assert!(parse_condition("some_flag").is_ok());
-    }
-
     #[test]
     fn context_dotted_fallback() {
         let outcome = make_outcome(StageStatus::Success);

lib/crates/fabro-workflows/src/context/keys.rs

@@ -1,7 +1,7 @@
-// Static context key constants and helper functions for dynamic keys.
-//
-// All context keys used across the engine, handlers, and preamble are
-// defined here to prevent typos and improve discoverability.
+//! Static context key constants and helper functions for dynamic keys.
+//!
+//! All context keys used across the engine, handlers, and preamble are
+//! defined here to prevent typos and improve discoverability.
 
 // --- Top-level keys ---
 pub const CURRENT_NODE: &str = "current_node";

lib/crates/fabro-workflows/src/error.rs

@@ -426,6 +426,12 @@ impl From<fabro_graphviz::error::GraphvizError> for FabroError {
     }
 }
 
+impl From<fabro_validate::ValidationError> for FabroError {
+    fn from(e: fabro_validate::ValidationError) -> Self {
+        Self::Validation(e.0)
+    }
+}
+
 pub type Result<T> = std::result::Result<T, FabroError>;
 
 #[cfg(test)]

lib/crates/fabro-workflows/src/handler/manager_loop.rs

@@ -61,7 +61,7 @@ fn parse_child_graph(node: &Node) -> Result<Graph, FabroError> {
         .and_then(|v| v.as_str())
     {
         let (graph, diagnostics) = prepare_from_file(std::path::Path::new(path))?;
-        fabro_validate::raise_on_errors(&diagnostics).map_err(|e| FabroError::Validation(e.0))?;
+        fabro_validate::raise_on_errors(&diagnostics)?;
         return Ok(graph);
     }
     Err(FabroError::handler("No child workflow source".to_string()))

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

@@ -106,7 +106,7 @@ pub fn prepare_from_file(path: &Path) -> Result<(Graph, Vec<Diagnostic>), FabroE
 pub fn prepare_from_source(dot_source: &str) -> Result<Graph, FabroError> {
     let builder = WorkflowBuilder::new();
     let (graph, diagnostics) = builder.prepare(dot_source)?;
-    fabro_validate::raise_on_errors(&diagnostics).map_err(|e| FabroError::Validation(e.0))?;
+    fabro_validate::raise_on_errors(&diagnostics)?;
     Ok(graph)
 }