fix(notes): page PhotoPrism server-side so /notes shows every captioned photo

Client-side paging of listPhotosWithNotes stopped early for BasePath users:
the sidecar post-filters each page by BasePath, so a full upstream page can
arrive short, tripping the `length < PAGE` end condition before the library
is exhausted — hiding notes past the first slice.

Add GET /api/sidecar/notes: the sidecar pages /api/v1/photos to completion
(keying the loop off the raw upstream page length), filters to non-empty
Caption under the caller's BasePath, dedupes by UID, and returns the set.
listPhotosWithNotes now calls this single endpoint.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

sidecar/handlers_photos.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"encoding/json"
+	"fmt"
 	"net/http"
 	"strings"
 
@@ -70,4 +71,71 @@ func handlePhotos(pp *ppClient) gin.HandlerFunc {
 		c.Header("X-Count", itoa(len(filtered)))
 		c.JSON(http.StatusOK, filtered)
 	}
-}
+}
+
+// handleNotes pages PhotoPrism's photo list to completion and returns only
+// photos carrying a non-empty Caption (mule-image's "Note"), scoped to the
+// caller's BasePath. Paging server-side is what makes this correct: the
+// client can't tell when the *BasePath-filtered* list is exhausted (a full
+// upstream page can filter down to a short — or empty — slice), but here we
+// can key the loop off the raw upstream page length.
+//
+// Route: GET /api/sidecar/notes  (behind requireSession)
+func handleNotes(pp *ppClient) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		token := ctxToken(c)
+		basePath := ctxBasePath(c)
+		prefix := basePath + "/"
+
+		const pageSize = 1000
+		out := make([]map[string]any, 0, 64)
+		seen := make(map[string]struct{})
+
+		for offset := 0; ; offset += pageSize {
+			path := fmt.Sprintf("/api/v1/photos?count=%d&offset=%d&merged=true&order=newest", pageSize, offset)
+			resp, err := pp.call(c.Request.Context(), http.MethodGet, path, token, nil)
+			if err != nil || !resp.OK {
+				c.JSON(http.StatusBadGateway, gin.H{"error": "upstream photos request failed"})
+				return
+			}
+
+			var photos []map[string]any
+			if err := json.Unmarshal(resp.Body, &photos); err != nil {
+				c.JSON(http.StatusBadGateway, gin.H{"error": "unexpected photos response"})
+				return
+			}
+			rawLen := len(photos)
+
+			for _, ph := range photos {
+				// BasePath scope — same rule as handlePhotos.
+				if basePath != "" {
+					pathStr, _ := ph["FileName"].(string)
+					if pathStr != basePath && !strings.HasPrefix(pathStr, prefix) {
+						continue
+					}
+				}
+				// Non-empty caption only.
+				caption, _ := ph["Caption"].(string)
+				if strings.TrimSpace(caption) == "" {
+					continue
+				}
+				// Dedupe by UID — `merged` can still repeat a photo at a page seam.
+				uid, _ := ph["UID"].(string)
+				if uid != "" {
+					if _, ok := seen[uid]; ok {
+						continue
+					}
+					seen[uid] = struct{}{}
+				}
+				out = append(out, ph)
+			}
+
+			// A short upstream page means PhotoPrism has no more rows.
+			if rawLen < pageSize {
+				break
+			}
+		}
+
+		c.JSON(http.StatusOK, out)
+	}
+}

sidecar/main.go

@@ -108,6 +108,10 @@ func main() {
 									// tabs only show photos the user owns.
 									auth.GET("/timeline", handlePhotos(pp))
 
+									// Photos carrying a Note (Caption) — pages PhotoPrism fully so
+									// the /notes view isn't capped to the newest slice.
+									auth.GET("/notes", handleNotes(pp))
+
 									// User-scoped folders — post-filters the folder tree by BasePath
 									// so the sidebar shows only folders under the user's library root.
 									auth.GET("/folders", handleFoldersProxy(pp))