Add PDF file attachments to components

- Upload PDFs, rename them (conflict-checked), delete them
- Link/unlink files per component (many components can share a file)
- File picker dialog: browse existing files, rename inline, upload new
- Component detail shows linked files as clickable links
- Files stored in data/pdfs/, served at /pdf/:filename
- KV prefix: pdf:

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

public/lib/api.mjs

@@ -44,6 +44,21 @@ export const create_component_template  = (body) => req('POST', '/api/component-
 export const update_component_template  = (id, body) => req('PUT', `/api/component-templates/${id}`, body);
 export const delete_component_template  = (id) => req('DELETE', `/api/component-templates/${id}`);
 
+// PDF files
+export const get_pdfs    = () => req('GET', '/api/pdfs');
+export const rename_pdf  = (id, display_name) => req('PUT', `/api/pdfs/${id}`, { display_name });
+export const delete_pdf  = (id) => req('DELETE', `/api/pdfs/${id}`);
+
+export async function upload_pdf(file, display_name) {
+	const form = new FormData();
+	form.append('file', file);
+	if (display_name) form.append('display_name', display_name);
+	const res = await fetch('/api/pdfs', { method: 'POST', body: form });
+	const data = await res.json();
+	if (!data.ok) throw new Error(data.error ?? 'Upload failed');
+	return data;
+}
+
 // Grid images
 export const get_grids        = () => req('GET', '/api/grid-images');
 export const get_grid         = (id) => req('GET', `/api/grid-images/${id}`);