feat(core): notification inbox infinite scroll + command palette fix (+ pending WIP)

消息中心:全量渲染 → 真·后端分页滚动加载
- backend(ops/views): NotificationPagination(10/页,page_size 可覆盖)+
  响应回 type_counts(按收件人绝对计数,不受分页/搜索影响)
- frontend(messages): 自管分页,滚到底加载下一批;tab/搜索走服务端并重置到第1页;
  代号作废在途旧请求防切换卡空白;乐观标已读;「已加载 X / Y」分母用当前筛选总数
- api/App/types: listNotifications 支持 page/page_size/search;allNotifications 携带 type_counts

命令面板(侧边栏搜索):修复点开后 UI 错位
- app-shell: 遮罩 className 漏了基类 shell-command-bg(只有 .show)致无定位塌到左下;
  补回基类 + header 类名对齐 .shell-command-h
- messages-page.css: 工作台收进视口高度,收件箱在面板内滚动

本次提交一并带入此前若干未提交 WIP(account/ai-tools/library/pipeline/products/settings +
accounts/ai/assets/billing/projects 后端),按用户要求整体推 dev。

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

core/backend/apps/projects/services/export.py

@@ -44,6 +44,19 @@ def _download_asset_primary_file(asset, target_path: Path) -> None:
     target_path.write_bytes(response.content)
 
 
+def _has_audio_stream(path: Path) -> bool:
+    """探测视频文件是否含音频流(决定是否保留该片段的原声/人声)。ffprobe 失败时保守按无声处理。"""
+    try:
+        proc = subprocess.run(
+            ["ffprobe", "-v", "error", "-select_streams", "a", "-show_entries",
+             "stream=index", "-of", "csv=p=0", str(path)],
+            capture_output=True, timeout=60,
+        )
+        return bool(proc.stdout.strip())
+    except Exception:  # noqa: BLE001
+        return False
+
+
 def _load_font(size: int):
     from PIL import ImageFont
 
@@ -123,9 +136,14 @@ def _output_starts(specs: list[dict], xfade: float) -> tuple[list[float], float]
     return starts, max(0.1, total)
 
 
+_AFMT = "aformat=sample_fmts=fltp:sample_rates=44100:channel_layouts=stereo"
+
+
 def _build_export_command(*, n: int, specs: list[dict], starts: list[float], total: float,
                           transition: str, sub_overlays: list[tuple[str, float, float]],
-                          bgm_name: str | None, bgm_volume: float) -> list[str]:
+                          bgm_name: str | None, bgm_volume: float,
+                          has_audio: list[bool] | None = None) -> list[str]:
+    has_audio = has_audio or [False] * n
     parts: list[str] = []
     for i, s in enumerate(specs):
         parts.append(
@@ -153,8 +171,30 @@ def _build_export_command(*, n: int, specs: list[dict], starts: list[float], tot
             f"[{vlabel}][{idx}:v]overlay=x=(W-w)/2:y=H-h-150:enable='between(t,{start:.3f},{end:.3f})'[{out}]"
         )
         vlabel = out
-    if bgm_name:
-        parts.append(f"[{n}:a]volume={bgm_volume:.3f},atrim=0:{total:.3f},asetpts=PTS-STARTPTS[aout]")
+
+    # 音频:片段自带的人声/原声必须保留(有声片段取原音轨,无声片段补等长静音,否则 concat 会缺流);
+    # 若另挂了 BGM,则把 BGM 混到原声之上(amix,normalize=0 不自动衰减原声音量)。
+    # 三种片段全无声且无 BGM 时,保持旧行为=纯视频不带音轨。
+    want_audio = any(has_audio) or bool(bgm_name)
+    audio_label: str | None = None
+    if want_audio:
+        for i, s in enumerate(specs):
+            if has_audio[i]:
+                parts.append(
+                    f"[{i}:a]atrim=start={s['ts']:.3f}:end={s['te']:.3f},asetpts=PTS-STARTPTS,{_AFMT}[a{i}]"
+                )
+            else:
+                parts.append(
+                    f"anullsrc=channel_layout=stereo:sample_rate=44100,atrim=0:{s['dur']:.3f},"
+                    f"asetpts=PTS-STARTPTS,{_AFMT}[a{i}]"
+                )
+        parts.append("".join(f"[a{i}]" for i in range(n)) + f"concat=n={n}:v=0:a=1[avoice0]")
+        parts.append(f"[avoice0]atrim=0:{total:.3f},asetpts=PTS-STARTPTS[avoice]")
+        audio_label = "avoice"
+        if bgm_name:
+            parts.append(f"[{n}:a]volume={bgm_volume:.3f},atrim=0:{total:.3f},asetpts=PTS-STARTPTS,{_AFMT}[abgm]")
+            parts.append("[avoice][abgm]amix=inputs=2:duration=longest:dropout_transition=0:normalize=0[aout]")
+            audio_label = "aout"
 
     cmd = ["ffmpeg", "-y"]
     for i in range(n):
@@ -164,10 +204,10 @@ def _build_export_command(*, n: int, specs: list[dict], starts: list[float], tot
     for png, _s, _e in sub_overlays:
         cmd += ["-loop", "1", "-i", png]
     cmd += ["-filter_complex", ";".join(parts), "-map", f"[{vlabel}]"]
-    if bgm_name:
-        cmd += ["-map", "[aout]"]
+    if audio_label:
+        cmd += ["-map", f"[{audio_label}]"]
     cmd += ["-c:v", "libx264", "-pix_fmt", "yuv420p", "-r", "30", "-preset", "veryfast"]
-    if bgm_name:
+    if audio_label:
         cmd += ["-c:a", "aac", "-b:a", "192k"]
     cmd += ["-t", f"{total:.3f}", "-movflags", "+faststart", "output.mp4"]
     return cmd
@@ -237,6 +277,8 @@ def run_export_job(export_job_id: str) -> ExportJob:
         tmp = Path(tmp_dir)
         for index, clip in enumerate(clips):
             _download_asset_primary_file(clip.asset, tmp / f"clip{index}.mp4")
+        # 逐片段探测是否自带音轨:有声→保留原声,无声→补静音(见 _build_export_command)
+        has_audio = [_has_audio_stream(tmp / f"clip{index}.mp4") for index in range(len(clips))]
 
         bgm_name = None
         if bgm_track is not None and bgm_track.asset_id:
@@ -258,6 +300,7 @@ def run_export_job(export_job_id: str) -> ExportJob:
         command = _build_export_command(
             n=len(clips), specs=specs, starts=starts, total=total, transition=transition,
             sub_overlays=sub_overlays, bgm_name=bgm_name, bgm_volume=(bgm_track.volume / 100.0) if bgm_track else 1.0,
+            has_audio=has_audio,
         )
         proc = subprocess.run(command, cwd=str(tmp), capture_output=True)
         if proc.returncode != 0: