fix: normalize hyphenated folder names in infer_type_from_folder()

Split on hyphens and underscores, capitalize each word, join with
spaces. E.g. monday-ideas → Monday Ideas, key-result → Key Result.
This prevents duplicate sidebar sections when folder name differs
from the Type file title.

Bump CACHE_VERSION to 5 to force rescan on existing caches.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src-tauri/src/vault/cache.rs

@@ -7,7 +7,7 @@ use super::{parse_md_file, scan_vault, VaultEntry};
 // --- Vault Cache ---
 
 /// Bump this when VaultEntry fields change to force a full rescan.
-const CACHE_VERSION: u32 = 4;
+const CACHE_VERSION: u32 = 5;
 
 #[derive(Debug, Serialize, Deserialize)]
 struct VaultCache {

src-tauri/src/vault/mod.rs

@@ -14,8 +14,8 @@ pub use rename::{rename_note, RenameResult};
 pub use trash::{delete_note, purge_trash};
 
 use parsing::{
-    capitalize_first, contains_wikilink, count_body_words, extract_outgoing_links, extract_snippet,
-    extract_title, parse_iso_date,
+    contains_wikilink, count_body_words, extract_outgoing_links, extract_snippet, extract_title,
+    parse_iso_date, title_case_folder,
 };
 
 use gray_matter::engine::YAML;
@@ -274,7 +274,7 @@ fn infer_type_from_folder(folder: &str) -> String {
         "month" => "Month",
         "essay" => "Essay",
         "evergreen" => "Evergreen",
-        _ => return capitalize_first(folder),
+        _ => return title_case_folder(folder),
     }
     .to_string()
 }
@@ -960,6 +960,28 @@ References:
         assert_eq!(entry.is_a, Some("Recipe".to_string()));
     }
 
+    #[test]
+    fn test_infer_type_from_hyphenated_folder_title_cases() {
+        let dir = TempDir::new().unwrap();
+        let cases = vec![
+            ("monday-ideas", "Monday Ideas"),
+            ("key-result", "Key Result"),
+            ("my_custom_type", "My Custom Type"),
+            ("mix-and_match", "Mix And Match"),
+        ];
+        for (folder, expected) in cases {
+            create_test_file(dir.path(), &format!("{}/test.md", folder), "# Test\n");
+            let entry = parse_md_file(&dir.path().join(folder).join("test.md")).unwrap();
+            assert_eq!(
+                entry.is_a,
+                Some(expected.to_string()),
+                "folder '{}' should infer type '{}'",
+                folder,
+                expected
+            );
+        }
+    }
+
     #[test]
     fn test_infer_type_frontmatter_overrides_folder() {
         let dir = TempDir::new().unwrap();

src-tauri/src/vault/parsing.rs

@@ -195,6 +195,16 @@ pub(super) fn capitalize_first(s: &str) -> String {
     }
 }
 
+/// Title-case a folder name: split on hyphens and underscores, capitalize each word, join with spaces.
+/// Example: "monday-ideas" → "Monday Ideas", "key_result" → "Key Result"
+pub(super) fn title_case_folder(s: &str) -> String {
+    s.split(|c| c == '-' || c == '_')
+        .filter(|w| !w.is_empty())
+        .map(|w| capitalize_first(w))
+        .collect::<Vec<_>>()
+        .join(" ")
+}
+
 /// Parse an ISO 8601 date string to Unix timestamp (seconds since epoch).
 /// Handles "2025-05-23T14:35:00.000Z" and "2025-05-23" formats.
 pub(super) fn parse_iso_date(date_str: &str) -> Option<u64> {
@@ -457,6 +467,29 @@ mod tests {
         assert_eq!(capitalize_first("a"), "A");
     }
 
+    // --- title_case_folder tests ---
+
+    #[test]
+    fn test_title_case_folder_hyphenated() {
+        assert_eq!(title_case_folder("monday-ideas"), "Monday Ideas");
+        assert_eq!(title_case_folder("key-result"), "Key Result");
+    }
+
+    #[test]
+    fn test_title_case_folder_underscored() {
+        assert_eq!(title_case_folder("my_custom_type"), "My Custom Type");
+    }
+
+    #[test]
+    fn test_title_case_folder_single_word() {
+        assert_eq!(title_case_folder("recipe"), "Recipe");
+    }
+
+    #[test]
+    fn test_title_case_folder_empty() {
+        assert_eq!(title_case_folder(""), "");
+    }
+
     // --- without_h1_line tests ---
 
     #[test]