chore: remove obsolete APIs (register, probe, n8n, videos, people)

- Remove /api/v1/register (replaced by /api/v1/files/register)
- Remove /api/v1/probe (replaced by /api/v1/files/:uuid)
- Remove /api/v1/n8n/... (n8n workflow only)
- Remove /api/v1/unregister (high risk)
- Remove /api/v1/videos list (replaced by /api/v1/files)
- Remove /api/v1/people (merged into /api/v1/identities)
- Clean up dead code and unused structs

src/core/db/postgres_db.rs

@@ -209,7 +209,7 @@ impl From<VideoRow> for VideoRecord {
             width: row.width.unwrap_or(0) as u32,
             height: row.height.unwrap_or(0) as u32,
             fps: row.fps.unwrap_or(0.0),
-            probe_json: row.probe_json.map(|v| v.to_string()),
+            probe_json: row.probe_json,
             storage: StorageStatus {
                 fs_video: row.fs_video.unwrap_or(false),
                 fs_json: row.fs_json.unwrap_or(false),
@@ -243,7 +243,7 @@ pub struct VideoRecord {
     pub width: u32,
     pub height: u32,
     pub fps: f64,
-    pub probe_json: Option<String>,
+    pub probe_json: Option<serde_json::Value>,
     pub storage: StorageStatus,
     pub status: VideoStatus,
     pub processing_status: Option<serde_json::Value>,
@@ -695,7 +695,7 @@ impl PostgresDb {
         }
 
         // Videos
-        sqlx::query("CREATE TABLE IF NOT EXISTS videos (id SERIAL PRIMARY KEY, file_uuid VARCHAR(32) UNIQUE NOT NULL, file_path TEXT NOT NULL, file_name TEXT NOT NULL, duration DOUBLE PRECISION, width INTEGER, height INTEGER, fps DOUBLE PRECISION, probe_json TEXT, fs_video BOOLEAN DEFAULT FALSE, fs_json BOOLEAN DEFAULT FALSE, psql_chunk BOOLEAN DEFAULT FALSE, pobject_chunk BOOLEAN DEFAULT FALSE, mobject_chunk BOOLEAN DEFAULT FALSE, pvector_chunk BOOLEAN DEFAULT FALSE, qvector_chunk BOOLEAN DEFAULT FALSE, created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP, updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP)").execute(pool).await?;
+        sqlx::query("CREATE TABLE IF NOT EXISTS videos (id SERIAL PRIMARY KEY, file_uuid VARCHAR(32) UNIQUE NOT NULL, file_path TEXT NOT NULL, file_name TEXT NOT NULL, duration DOUBLE PRECISION, width INTEGER, height INTEGER, fps DOUBLE PRECISION, probe_json jsonb, fs_video BOOLEAN DEFAULT FALSE, fs_json BOOLEAN DEFAULT FALSE, psql_chunk BOOLEAN DEFAULT FALSE, pobject_chunk BOOLEAN DEFAULT FALSE, mobject_chunk BOOLEAN DEFAULT FALSE, pvector_chunk BOOLEAN DEFAULT FALSE, qvector_chunk BOOLEAN DEFAULT FALSE, created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP, updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP)").execute(pool).await?;
         sqlx::query("CREATE INDEX IF NOT EXISTS idx_videos_file_uuid ON videos(file_uuid)")
             .execute(pool)
             .await?;

src/core/ingestion.rs

@@ -171,7 +171,7 @@ impl IngestionService {
             width,
             height,
             fps,
-            probe_json: Some(probe_json_str),
+            probe_json: serde_json::from_str(&probe_json_str).ok(),
             storage: Default::default(),
             status: VideoStatus::Pending,
             processing_status: Some(serde_json::json!({"phase": "REGISTERED"})),