feat(discover): map .razor to C# so Blazor components are discovered

A .razor file had no entry in EXT_TABLE, so discovery skipped it entirely
and a Blazor application produced no graph nodes for any of its
components. The only way in was an undocumented extra_extensions entry in
a per-project .codebase-memory.json.

Map .razor to CBM_LANG_CSHARP. This is best-effort by design: the C#
grammar recovers the @code block, while the surrounding markup lands in
ERROR regions and is reported through parse_partial. That is strictly
more than the Module-and-imports the other markup-hosted languages
(Vue, Svelte, Astro) extract today, and it needs no new grammar.

Covered by tests/test_language.c:lang_ext_razor.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Signed-off-by: The1nk <23087600+The1nk@users.noreply.github.com>

Author: The1nk

src/discover/language.c

@@ -49,6 +49,11 @@ static const ext_entry_t EXT_TABLE[] = {
 
     /* C# */
     {".cs", CBM_LANG_CSHARP},
+    /* Blazor components. The C# grammar recovers the @code block; the
+     * surrounding markup parses as ERROR regions and is reported via
+     * parse_partial, which is why this is a best-effort mapping rather
+     * than a dedicated grammar. */
+    {".razor", CBM_LANG_CSHARP},
 
     /* Clojure */
     {".clj", CBM_LANG_CLOJURE},

tests/test_language.c

@@ -89,6 +89,14 @@ TEST(lang_ext_csharp) {
     ASSERT_EQ(cbm_language_for_extension(".cs"), CBM_LANG_CSHARP);
     PASS();
 }
+/* Blazor components were unmapped, so a .razor file was never discovered at
+ * all: indexing a Blazor app produced no nodes for any component, and reaching
+ * them required an undocumented extra_extensions entry in a per-project
+ * .codebase-memory.json. */
+TEST(lang_ext_razor) {
+    ASSERT_EQ(cbm_language_for_extension(".razor"), CBM_LANG_CSHARP);
+    PASS();
+}
 TEST(lang_ext_php) {
     ASSERT_EQ(cbm_language_for_extension(".php"), CBM_LANG_PHP);
     PASS();
@@ -1079,6 +1087,7 @@ SUITE(language) {
     RUN_TEST(lang_ext_h);
     RUN_TEST(lang_ext_ixx);
     RUN_TEST(lang_ext_csharp);
+    RUN_TEST(lang_ext_razor);
     RUN_TEST(lang_ext_php);
     RUN_TEST(lang_ext_lua);
     RUN_TEST(lang_ext_scala);