fix(scholars): improve validation, fix delete, add status badges

- Extract scholar ID parsing to dedicated module with robust URL
  handling (trailing slashes, fragments, extra query params, encoded
  characters) and per-token error feedback showing why each invalid
  entry was skipped
- Wrap delete_scholar DB commit in IntegrityError handler so cascade
  failures return a proper API error instead of 500
- Add ScholarStatusBadges component showing Pending/Failed/Partial/OK
  badges on scholar rows based on baseline_completed and last_run_status
- Show Pending badge in ScholarSettingsModal for unscraped scholars
- Surface failed_count and partial_count in dashboard latest run summary
  and recent run list items
- Extend backend validator tests with edge cases (empty, whitespace,
  unicode, URL-as-ID)
- Add integration tests for DELETE 404, DELETE with cascade, and POST
  with corrupted scholar_id
- Add comprehensive frontend tests for parsing logic and component
  behavior

tests/unit/test_scholar_validators.py

@@ -42,6 +42,34 @@ class TestValidateScholarId:
         with pytest.raises(ScholarServiceError, match="12"):
             validate_scholar_id("ABCDEF12345!")
 
+    def test_rejects_empty_string(self) -> None:
+        with pytest.raises(ScholarServiceError, match="12"):
+            validate_scholar_id("")
+
+    def test_rejects_whitespace_only(self) -> None:
+        with pytest.raises(ScholarServiceError, match="12"):
+            validate_scholar_id("   ")
+
+    def test_rejects_embedded_spaces(self) -> None:
+        with pytest.raises(ScholarServiceError, match="12"):
+            validate_scholar_id("ABCDEF 12345")
+
+    def test_rejects_tab_characters(self) -> None:
+        with pytest.raises(ScholarServiceError, match="12"):
+            validate_scholar_id("ABCDEF\t12345")
+
+    def test_rejects_url_as_id(self) -> None:
+        with pytest.raises(ScholarServiceError, match="12"):
+            validate_scholar_id("https://scholar.google.com/citations?user=ABCDEF123456")
+
+    def test_rejects_newline_in_id(self) -> None:
+        with pytest.raises(ScholarServiceError, match="12"):
+            validate_scholar_id("ABCDEF\n12345")
+
+    def test_rejects_unicode_characters(self) -> None:
+        with pytest.raises(ScholarServiceError, match="12"):
+            validate_scholar_id("ABCDEF12345\u00e9")
+
 
 class TestNormalizeDisplayName:
     def test_returns_stripped_name(self) -> None: