Remove dead .save() methods, write_run_status, save_json, and ConclusionExt

These disk-write methods had no production callers — all data is now
persisted via events in SlateDB. Removes save_json helper, .save() from
RunRecord/StartRecord/Checkpoint traits, the entire ConclusionExt trait,
and the write_run_status function.

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

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

@@ -29,18 +29,6 @@ pub(crate) fn millis_u64(d: std::time::Duration) -> u64 {
     u64::try_from(d.as_millis()).unwrap_or(u64::MAX)
 }
 
-/// Save a value as pretty-printed JSON to a file.
-pub(crate) fn save_json<T: serde::Serialize>(
-    value: &T,
-    path: &std::path::Path,
-    label: &str,
-) -> error::Result<()> {
-    let json = serde_json::to_string_pretty(value)
-        .map_err(|e| error::FabroError::Checkpoint(format!("{label} serialize failed: {e}")))?;
-    std::fs::write(path, json)?;
-    Ok(())
-}
-
 /// Load a value from a JSON file.
 pub(crate) fn load_json<T: DeserializeOwned>(
     path: &std::path::Path,

lib/crates/fabro-workflow/src/records/checkpoint.rs

@@ -22,7 +22,6 @@ pub trait CheckpointExt {
     ) -> Self
     where
         Self: Sized;
-    fn save(&self, path: &Path) -> CrateResult<()>;
     fn load(path: &Path) -> CrateResult<Self>
     where
         Self: Sized;
@@ -55,11 +54,6 @@ impl CheckpointExt for Checkpoint {
         }
     }
 
-    fn save(&self, path: &Path) -> CrateResult<()> {
-        tracing::debug!(path = %path.display(), node = %self.current_node, "Saving checkpoint");
-        crate::save_json(self, path, "checkpoint")
-    }
-
     fn load(path: &Path) -> CrateResult<Self> {
         tracing::debug!(path = %path.display(), "Loading checkpoint");
         crate::load_json(path, "checkpoint")

lib/crates/fabro-workflow/src/records/conclusion.rs

@@ -1,22 +1 @@
-use std::path::Path;
-
 pub use fabro_types::conclusion::{Conclusion, StageSummary};
-
-use crate::error::Result as CrateResult;
-
-pub trait ConclusionExt {
-    fn save(&self, path: &Path) -> CrateResult<()>;
-    fn load(path: &Path) -> CrateResult<Self>
-    where
-        Self: Sized;
-}
-
-impl ConclusionExt for Conclusion {
-    fn save(&self, path: &Path) -> CrateResult<()> {
-        crate::save_json(self, path, "conclusion")
-    }
-
-    fn load(path: &Path) -> CrateResult<Self> {
-        crate::load_json(path, "conclusion")
-    }
-}

lib/crates/fabro-workflow/src/records/mod.rs

@@ -4,6 +4,6 @@ mod run;
 mod start;
 
 pub use checkpoint::{Checkpoint, CheckpointExt};
-pub use conclusion::{Conclusion, ConclusionExt, StageSummary};
+pub use conclusion::{Conclusion, StageSummary};
 pub use run::{RunRecord, RunRecordExt};
 pub use start::{StartRecord, StartRecordExt};

lib/crates/fabro-workflow/src/records/run.rs

@@ -10,7 +10,6 @@ pub trait RunRecordExt {
     fn file_name() -> &'static str
     where
         Self: Sized;
-    fn save(&self, run_dir: &Path) -> CrateResult<()>;
     fn load(run_dir: &Path) -> CrateResult<Self>
     where
         Self: Sized;
@@ -25,10 +24,6 @@ impl RunRecordExt for RunRecord {
         FILE_NAME
     }
 
-    fn save(&self, run_dir: &Path) -> CrateResult<()> {
-        crate::save_json(self, &run_dir.join(FILE_NAME), "run record")
-    }
-
     fn load(run_dir: &Path) -> CrateResult<Self> {
         crate::load_json(&run_dir.join(FILE_NAME), "run record")
     }

lib/crates/fabro-workflow/src/records/start.rs

@@ -10,7 +10,6 @@ pub trait StartRecordExt {
     fn file_name() -> &'static str
     where
         Self: Sized;
-    fn save(&self, run_dir: &Path) -> CrateResult<()>;
     fn load(run_dir: &Path) -> CrateResult<Self>
     where
         Self: Sized;
@@ -21,10 +20,6 @@ impl StartRecordExt for StartRecord {
         FILE_NAME
     }
 
-    fn save(&self, run_dir: &Path) -> CrateResult<()> {
-        crate::save_json(self, &run_dir.join(FILE_NAME), "start record")
-    }
-
     fn load(run_dir: &Path) -> CrateResult<Self> {
         crate::load_json(&run_dir.join(FILE_NAME), "start record")
     }

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

@@ -5,26 +5,15 @@ pub use fabro_types::status::{
 };
 
 pub trait RunStatusRecordExt {
-    fn save(&self, path: &Path) -> std::io::Result<()>;
     fn load(path: &Path) -> std::io::Result<Self>
     where
         Self: Sized;
 }
 
 impl RunStatusRecordExt for RunStatusRecord {
-    fn save(&self, path: &Path) -> std::io::Result<()> {
-        let json = serde_json::to_string_pretty(self).map_err(std::io::Error::other)?;
-        std::fs::write(path, json)
-    }
-
     fn load(path: &Path) -> std::io::Result<Self> {
         let data = std::fs::read_to_string(path)?;
         serde_json::from_str(&data)
             .map_err(|e| std::io::Error::new(std::io::ErrorKind::InvalidData, e))
     }
 }
-
-pub fn write_run_status(run_dir: &Path, status: RunStatus, reason: Option<StatusReason>) {
-    let record = RunStatusRecord::new(status, reason);
-    let _ = record.save(&run_dir.join("status.json"));
-}

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

@@ -16,7 +16,7 @@ use crate::handler::HandlerRegistry;
 use crate::outcome::Outcome;
 use crate::pipeline;
 use crate::pipeline::types::Initialized;
-use crate::records::{Checkpoint, CheckpointExt};
+use crate::records::Checkpoint;
 use crate::run_options::RunOptions;
 
 struct InitializedOptions {
@@ -192,7 +192,9 @@ async fn persist_run_artifacts_for_tests(run_store: &SlateRunStore, run_dir: &st
     };
 
     if let Some(checkpoint) = state.checkpoint.as_ref() {
-        let _ = checkpoint.save(&run_dir.join("checkpoint.json"));
+        if let Ok(json) = serde_json::to_string_pretty(checkpoint) {
+            let _ = std::fs::write(run_dir.join("checkpoint.json"), json);
+        }
     }
 
     if let Some(final_patch) = state.final_patch.as_ref() {