Some bug fixes:

- logging: LogToFile shadowed the package-level fileLogger, so
  IsFileLogger was always false and Shutdown never closed the file
- logging: replace IsJSONHandler's unsafe reflection into slog
  internals with a *slog.JSONHandler type check
- cli: fail if the log file can't be opened instead of silently
  logging to the terminal; return the log shutdown error from Finish
- build.sh: -X flags used the wrong module path, so the version, build
  time and commit were never stamped

internal/cli/options.go

@@ -1,6 +1,7 @@
 package cli
 
 import (
+	"fmt"
 	"log/slog"
 
 	"git.avsdev.uk/Go/job-search/internal/config"
@@ -58,8 +59,8 @@ func (o *Options) RunSetup(
 		if !terminalLog {
 			if len(conf.Logging.File) == 0 {
 				slog.Warn("No log file configured, remaining in console logging mode!")
-			} else {
-				logging.LogToFile(conf.Logging.File)
+			} else if err := logging.LogToFile(conf.Logging.File); err != nil {
+				return nil, fmt.Errorf("opening log file: %w", err)
 			}
 		}
 	}
@@ -70,7 +71,7 @@ func (o *Options) RunSetup(
 // Finish shuts down any open file logger
 func (o *Options) Finish() error {
 	if logging.IsFileLogger() {
-		logging.Shutdown()
+		return logging.Shutdown()
 	}
 
 	return nil