fix(simulation): address PR #89 review — version comment, settings contract, docs, dead process recovery

Must-fix: protocol version comment now references PROTOCOL_VERSION
(no hardcoded number), settings delete is idempotent no-op.

Suggestions addressed: BehaviorModifier dedup claim dropped, hash
collision safety documented, FK pragma in test store, columns_to_value
consolidated, modifier_hint mismatch logging, OffDuty test coverage,
batching tradeoff documented, unknown value_type warning, occluded
text risk documented, dead child respawn in voice worker, INJECT
block ambiguity documented.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/settings/mod.rs

@@ -139,6 +139,9 @@ pub fn process_settings_commands(
     };
 
     // Process all commands, last response wins (same tick batching).
+    // If multiple settings commands arrive in one tick, only the final response
+    // reaches the client. This is acceptable: the client sends one action per tick
+    // in normal use, and batch changes via RequestAll after bulk updates.
     for cmd in commands {
         match cmd {
             SettingsCommand::Change { ref key, ref value } => {
@@ -171,16 +174,13 @@ pub fn process_settings_commands(
                 });
             }
             SettingsCommand::Delete { ref key } => {
-                let deleted = store.delete(key);
+                // Idempotent: deleting a non-existent key is a silent no-op.
+                let _deleted = store.delete(key);
                 snapshot_buffer.pending_settings_response = Some(SettingsResponseWire {
                     success: true,
                     kind: "ack".into(),
                     settings: vec![],
-                    error: if deleted {
-                        None
-                    } else {
-                        Some(format!("setting not found: {}", key))
-                    },
+                    error: None,
                 });
             }
         }

server/src/settings/store.rs

@@ -49,6 +49,7 @@ impl SettingsStore {
     /// Open an in-memory database (for tests).
     pub fn open_in_memory() -> Result<Self, rusqlite::Error> {
         let conn = Connection::open_in_memory()?;
+        conn.execute_batch("PRAGMA foreign_keys = ON;")?;
         conn.execute(
             "CREATE TABLE settings (
                 player_id   TEXT    NOT NULL,
@@ -92,7 +93,7 @@ impl SettingsStore {
         match rows.next()? {
             Some(row) => {
                 let vtype: String = row.get(0)?;
-                Ok(Some(columns_to_value(&vtype, row)?))
+                Ok(Some(columns_to_value(&vtype, row, 1)?))
             }
             None => Ok(None),
         }
@@ -112,7 +113,7 @@ impl SettingsStore {
         while let Some(row) = rows.next()? {
             let key: String = row.get(0)?;
             let vtype: String = row.get(1)?;
-            let value = columns_to_value_offset(&vtype, row)?;
+            let value = columns_to_value(&vtype, row, 2)?;
             result.insert(key, value);
         }
         Ok(result)
@@ -158,33 +159,25 @@ fn value_to_columns(
     }
 }
 
-/// Read a SettingValue from a row where value columns start at index 1.
-/// Used by `get()` which selects (value_type, value_text, value_int, value_float, value_bool).
+/// Read a SettingValue from a row where value columns start at `offset`.
+/// `offset` is the index of the value_text column (value_int = offset+1, etc.).
+///
+/// Used by `get()` (offset=1) and `get_all()` (offset=2) which select different
+/// column prefixes before the value columns.
 fn columns_to_value(
     vtype: &str,
     row: &rusqlite::Row<'_>,
+    offset: usize,
 ) -> Result<SettingValue, rusqlite::Error> {
     match vtype {
-        "string" => Ok(SettingValue::String(row.get::<_, String>(1)?)),
-        "int" => Ok(SettingValue::Int(row.get::<_, i64>(2)?)),
-        "float" => Ok(SettingValue::Float(row.get::<_, f64>(3)?)),
-        "bool" => Ok(SettingValue::Bool(row.get::<_, bool>(4)?)),
-        other => Ok(SettingValue::String(format!("<unknown type: {}>", other))),
-    }
-}
-
-/// Read a SettingValue from a row where value columns start at index 2.
-/// Used by `get_all()` which selects (key, value_type, value_text, ...).
-fn columns_to_value_offset(
-    vtype: &str,
-    row: &rusqlite::Row<'_>,
-) -> Result<SettingValue, rusqlite::Error> {
-    match vtype {
-        "string" => Ok(SettingValue::String(row.get::<_, String>(2)?)),
-        "int" => Ok(SettingValue::Int(row.get::<_, i64>(3)?)),
-        "float" => Ok(SettingValue::Float(row.get::<_, f64>(4)?)),
-        "bool" => Ok(SettingValue::Bool(row.get::<_, bool>(5)?)),
-        other => Ok(SettingValue::String(format!("<unknown type: {}>", other))),
+        "string" => Ok(SettingValue::String(row.get::<_, String>(offset)?)),
+        "int" => Ok(SettingValue::Int(row.get::<_, i64>(offset + 1)?)),
+        "float" => Ok(SettingValue::Float(row.get::<_, f64>(offset + 2)?)),
+        "bool" => Ok(SettingValue::Bool(row.get::<_, bool>(offset + 3)?)),
+        other => {
+            tracing::warn!("unknown settings value_type '{}', treating as String", other);
+            Ok(SettingValue::String(format!("<unknown type: {}>", other)))
+        }
     }
 }