fix(history): add error logging to silent catch {} handlers (#167)

Replace empty catch {} handlers with proper error logging using
std.log.debug for consistency. This prevents persistence failures
from being silently swallowed.

Changes:
- History.add(): log save errors
- ReplHistory.load(): log load errors
- ReplHistory.saveBeforeExit(): log save errors

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

Author: Trinity Agent

src/tri/tri_history.zig

@@ -61,7 +61,9 @@ pub const History = struct {
         }
 
         // Save to file
-        self.save() catch {};
+        self.save() catch |err| {
+            std.log.debug("history save: {s}", .{@errorName(err)});
+        };
     }
 
     /// Navigate to previous command
@@ -252,7 +254,9 @@ pub const ReplHistory = struct {
 
     /// Load history from file
     pub fn load(self: *ReplHistory) !void {
-        self.history.load() catch {};
+        self.history.load() catch |err| {
+            std.log.debug("history load: {s}", .{@errorName(err)});
+        };
     }
 
     /// Save current input and clear
@@ -312,7 +316,9 @@ pub const ReplHistory = struct {
 
     /// Save history before exit
     pub fn saveBeforeExit(self: *ReplHistory) void {
-        self.history.save() catch {};
+        self.history.save() catch |err| {
+            std.log.debug("history save: {s}", .{@errorName(err)});
+        };
     }
 };