info_panel: render uncategorized tags under Other bucket

behavior change: tags that weren't in any section of
post.tag_categories (partial batch-API response, HTML scrape
returned empty, stale cache) used to silently disappear from the
info panel — the categorized loop only iterated categories, so
any tag without a cached label just didn't render.

Now after the known category sections, any remaining tags from
post.tag_list are collected into an 'Other:' section with a
neutral header. The tag is visible and clickable even when its
type code never made it into the cache.

Reported against Gelbooru posts with long character tag names
where the batch tag API was returning partial results and the
missing tags were just gone from the UI.

CHANGELOG.md

@@ -11,6 +11,7 @@
 ### Fixed
 - `category_fetcher._do_ensure` no longer permanently flips `_batch_api_works` to False when a transient network error drops a tag-API request mid-call; the unprobed path now routes through `_probe_batch_api`, which distinguishes clean 200-with-zero-matches (structurally broken, flip) from timeout/HTTP-error (transient, retry next call)
 - Bookmark→library save and bookmark Save As now plumb the active site's `CategoryFetcher` through to the filename template, so `%artist%`/`%character%` tokens render correctly instead of silently dropping out when saving a post that wasn't previewed first
+- Info panel no longer silently drops tags that failed to land in a cached category — any tag from `post.tag_list` not rendered under a known category section now appears in an "Other" bucket, so partial cache coverage can't make individual tags invisible
 
 ### Refactored
 - `category_fetcher` batch tag-API params are now built by a shared `_build_tag_api_params` helper instead of duplicated across `fetch_via_tag_api` and `_probe_batch_api`

booru_viewer/gui/info_panel.py

@@ -136,6 +136,7 @@ class InfoPanel(QWidget):
             # Display tags grouped by category. Colors come from the
             # tag*Color Qt Properties so a custom.qss can override any of
             # them via `InfoPanel { qproperty-tagCharacterColor: ...; }`.
+            rendered: set[str] = set()
             for category, tags in post.tag_categories.items():
                 color = self._category_color(category)
                 header = QLabel(f"{category}:")
@@ -145,6 +146,7 @@ class InfoPanel(QWidget):
                 )
                 self._tags_flow.addWidget(header)
                 for tag in tags:
+                    rendered.add(tag)
                     btn = QPushButton(tag)
                     btn.setFlat(True)
                     btn.setCursor(Qt.CursorShape.PointingHandCursor)
@@ -155,6 +157,27 @@ class InfoPanel(QWidget):
                     btn.setStyleSheet(style)
                     btn.clicked.connect(lambda checked, t=tag: self.tag_clicked.emit(t))
                     self._tags_flow.addWidget(btn)
+            # Safety net: any tag in post.tag_list that didn't land in
+            # a cached category (batch tag API returned partial results,
+            # HTML scrape fell short, cache stale, etc.) is still shown
+            # under an "Other" bucket so tags can't silently disappear
+            # from the info panel.
+            leftover = [t for t in post.tag_list if t and t not in rendered]
+            if leftover:
+                header = QLabel("Other:")
+                header.setStyleSheet(
+                    "font-weight: bold; margin-top: 6px; margin-bottom: 2px;"
+                )
+                self._tags_flow.addWidget(header)
+                for tag in leftover:
+                    btn = QPushButton(tag)
+                    btn.setFlat(True)
+                    btn.setCursor(Qt.CursorShape.PointingHandCursor)
+                    btn.setStyleSheet(
+                        "QPushButton { text-align: left; padding: 1px 4px; border: none; }"
+                    )
+                    btn.clicked.connect(lambda checked, t=tag: self.tag_clicked.emit(t))
+                    self._tags_flow.addWidget(btn)
         elif not self._categories_pending:
             # Flat tag fallback — only when no category fetch is
             # in-flight. When a fetch IS pending, leaving the tags