feat: add stripDatePrefix option for Jekyll-style filenames

Adds a new `stripDatePrefix` configuration option that removes
YYYY-MM-DD- prefixes from filenames when deriving slugs. This
supports Jekyll-style post naming where files like
`2024-01-15-my-post.md` should produce slug `my-post`.

packages/cli/src/commands/publish.ts

···
 			ignorePatterns: config.ignore,
 			slugField: config.frontmatter?.slugField,
 			removeIndexFromSlug: config.removeIndexFromSlug,
+			stripDatePrefix: config.stripDatePrefix,
 		});
 		s.stop(`Found ${posts.length} posts`);
 

packages/cli/src/commands/sync.ts

···
 			ignorePatterns: config.ignore,
 			slugField: config.frontmatter?.slugField,
 			removeIndexFromSlug: config.removeIndexFromSlug,
+			stripDatePrefix: config.stripDatePrefix,
 		});
 		s.stop(`Found ${localPosts.length} local posts`);
 

packages/cli/src/lib/config.ts

···
 	frontmatter?: FrontmatterMapping;
 	ignore?: string[];
 	removeIndexFromSlug?: boolean;
+	stripDatePrefix?: boolean;
 	textContentField?: string;
 	bluesky?: BlueskyConfig;
 }): string {
···
 
 	if (options.removeIndexFromSlug) {
 		config.removeIndexFromSlug = options.removeIndexFromSlug;
+	}
+
+	if (options.stripDatePrefix) {
+		config.stripDatePrefix = options.stripDatePrefix;
 	}
 
 	if (options.textContentField) {

packages/cli/src/lib/markdown.ts

···
 export interface SlugOptions {
 	slugField?: string;
 	removeIndexFromSlug?: boolean;
+	stripDatePrefix?: boolean;
 }
 
 export function getSlugFromOptions(
···
 	rawFrontmatter: Record<string, unknown>,
 	options: SlugOptions = {},
 ): string {
-	const { slugField, removeIndexFromSlug = false } = options;
+	const { slugField, removeIndexFromSlug = false, stripDatePrefix = false } = options;
 
 	let slug: string;
 
···
 		slug = slug.replace(/\/_?index$/, "");
 	}
 
+	// Strip Jekyll-style date prefix (YYYY-MM-DD-) from filename
+	if (stripDatePrefix) {
+		slug = slug.replace(/(^|\/)(\d{4}-\d{2}-\d{2})-/g, "$1");
+	}
+
 	return slug;
 }
 
···
 	ignorePatterns?: string[];
 	slugField?: string;
 	removeIndexFromSlug?: boolean;
+	stripDatePrefix?: boolean;
 }
 
 export async function scanContentDirectory(
···
 		ignorePatterns: ignore = [],
 		slugField,
 		removeIndexFromSlug,
+		stripDatePrefix,
 	} = options;
 
 	const patterns = ["**/*.md", "**/*.mdx"];
···
 				const slug = getSlugFromOptions(relativePath, rawFrontmatter, {
 					slugField,
 					removeIndexFromSlug,
+					stripDatePrefix,
 				});
 
 				posts.push({

packages/cli/src/lib/types.ts

···
 	frontmatter?: FrontmatterMapping; // Custom frontmatter field mappings
 	ignore?: string[]; // Glob patterns for files to ignore (e.g., ["_index.md", "**/drafts/**"])
 	removeIndexFromSlug?: boolean; // Remove "/index" or "/_index" suffix from paths (default: false)
+	stripDatePrefix?: boolean; // Remove YYYY-MM-DD- prefix from filenames (Jekyll-style, default: false)
 	textContentField?: string; // Frontmatter field to use for textContent instead of markdown body
 	bluesky?: BlueskyConfig; // Optional Bluesky posting configuration
 }