fix(workflows): workflow add detects local YAML files case-insensitively (#3633)

`workflow add` gated the local-file branches on a case-SENSITIVE
`.suffix in (".yml", ".yaml")` (the `--dev` branch and the plain
local-path branch), while every other YAML-file detector in the CLI
normalizes case: `workflow run` uses `source_path.suffix.lower()` and
`WorkflowEngine.load_workflow` uses `path.suffix.lower()`.

The result was an add/run inconsistency: `specify workflow run Sample.YAML`
loads the file, but `specify workflow add Sample.YAML` does not recognize
it as a local workflow — the `--dev` branch rejects it with "--dev source
must be a workflow YAML file ..." and the plain path falls through to a
catalog lookup that fails with "not found in catalog".

Add `.lower()` to both suffix reads so `workflow add` matches its siblings.
The lowercase happy path is unchanged.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/specify_cli/workflows/_commands.py

@@ -1555,7 +1555,7 @@ def workflow_add(
     # precedence over --from so a URL that would be ignored is never fetched.
     if dev:
         dev_path = Path(source).expanduser()
-        if dev_path.is_file() and dev_path.suffix in (".yml", ".yaml"):
+        if dev_path.is_file() and dev_path.suffix.lower() in (".yml", ".yaml"):
             _validate_and_install_local(dev_path, str(dev_path))
             return
         if dev_path.is_dir():
@@ -1714,7 +1714,7 @@ def workflow_add(
     # Try as a local file/directory
     source_path = Path(source)
     if source_path.exists():
-        if source_path.is_file() and source_path.suffix in (".yml", ".yaml"):
+        if source_path.is_file() and source_path.suffix.lower() in (".yml", ".yaml"):
             _validate_and_install_local(source_path, str(source_path))
             return
         elif source_path.is_dir():