Give -v to verbose, move --version to -V (closes #64)

urfave/cli's built-in version flag claimed -v, so "mfer -v --version"
failed to parse, and -v meant version at the root but verbose on
generate, check, freshen and fetch. Verbose is the more common meaning,
so the root now takes -v and -q too, the version flag takes -V, and a
-v or -q before the subcommand name applies to that subcommand.

User-visible changes: -v alone prints help with verbose logging, not
the version; use -V or --version. "mfer version" prints "mfer version
0.1.0 (...)", the same line as --version, instead of the bare
"0.1.0 (...)".

The error-message tests now send their log lines to io.Discard; they
were landing in other tests' output buffers.

Model: opus-4-8 (implementation); opus-5-5 (rework)

TODO.md

@@ -24,6 +24,8 @@ only thing left of the `chore/align-repo-policies` branch is the list below.
 
 # Completed Steps
 
+- 2026-09-21: fixed the `-v` collision between `--verbose` and `--version`;
+  verbose owns `-v`, and version answers to `--version` and `-V` (#64)
 - 2026-10-03: pinned the CLI error messages by driving the functions that emit
   them in `internal/cli/errmsg_test.go`, and made the freshen mtime-presence
   test distinguish an absent mtime from the epoch (#87)