refactor(frontend): foundation phase 0a — CSS extraction + NSFW persistence + last_error banner

Primeira parte do refactor frontend planejado. Sem mudar funcionalidade
visivel pro usuario, prepara o terreno pra fase 0b (parciais Jinja +
HTMX + Alpine) na proxima iteracao.

Backend foundation
- Persist over_18 do Reddit como coluna `nsfw` em posts (migration
  ALTER TABLE). Antes vinha em RedditPost mas era jogado fora; sem
  isso o NSFW gate da Fase 1 nao tem dado pra operar.
- POST /api/collector/clear-error pra dispensar o banner que mostra
  o `last_error` no header da UI.

CSS extraction (1063 → 0 inline)
- Move o bloco <style> inteiro do index.html (linhas 7-1069) para
  src/web/static/css/app.css. Index ja serve via <link>.
- Adiciona CSS custom properties no :root (cores principais) como
  base para tema; uso opcional, mantem cores hardcoded onde ja
  estavam pra evitar visual diff.
- Novos placeholders .error-banner, .nsfw-thumb, .discreet pra
  destravar Fase 1 sem nova mudanca de CSS.

UI observability
- Banner vermelho discreto no topo da pagina quando
  collector_status.last_error esta preenchido. updateStatus()
  alimenta; botao "Limpar" chama /api/collector/clear-error.
- Novo helper global showApiError(err, fallback) que LE o `detail`
  real do response (Response ou Error). Substitui as 22 chamadas
  de `showAlert('Erro de conexao', 'error')` espalhadas pelos
  handlers. Agora um 500 do server aparece com a mensagem real,
  nao com o generico que escondia o bug do compose :ro.

Resultado: index.html caiu de 3620 para 2575 linhas, sem refactor de
JS/HTML ainda. Cobertura e CI continuam verdes (151 testes).

pyproject.toml

@@ -7,7 +7,7 @@ packages = ["src"]
 
 [project]
 name = "reddit-media-collector"
-version = "1.0.3"
+version = "1.1.0"
 description = "Self-hosted media collector for Reddit with Immich integration"
 readme = "README.md"
 requires-python = ">=3.11"

src/database.py

@@ -38,6 +38,7 @@ class PostRecord:
     permalink: str | None = None  # Reddit permalink for Immich
     source_type: str | None = None  # 'subreddit' or 'user'
     flair: str | None = None  # Post flair for tagging
+    nsfw: bool = False  # Mirrors Reddit's over_18; powers UI NSFW gate
 
 
 class Database:
@@ -66,7 +67,8 @@ class Database:
                     file_hash TEXT,
                     permalink TEXT,
                     source_type TEXT,
-                    flair TEXT
+                    flair TEXT,
+                    nsfw INTEGER DEFAULT 0
                 )
             """)
             # Favorites table
@@ -84,6 +86,8 @@ class Database:
                 conn.execute("ALTER TABLE posts ADD COLUMN source_type TEXT")
             with suppress(sqlite3.OperationalError):
                 conn.execute("ALTER TABLE posts ADD COLUMN flair TEXT")
+            with suppress(sqlite3.OperationalError):
+                conn.execute("ALTER TABLE posts ADD COLUMN nsfw INTEGER DEFAULT 0")
             conn.execute("CREATE INDEX IF NOT EXISTS idx_subreddit ON posts(subreddit)")
             conn.execute("CREATE INDEX IF NOT EXISTS idx_file_hash ON posts(file_hash)")
             conn.execute("CREATE INDEX IF NOT EXISTS idx_downloaded ON posts(downloaded_at)")
@@ -139,8 +143,8 @@ class Database:
                 INSERT OR REPLACE INTO posts
                 (id, subreddit, author, title, url, media_url, media_type,
                  score, created_utc, downloaded_at, local_path, file_hash,
-                 permalink, source_type, flair)
-                VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+                 permalink, source_type, flair, nsfw)
+                VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
                 """,
                 (
                     post.id,
@@ -158,6 +162,7 @@ class Database:
                     post.permalink,
                     post.source_type,
                     post.flair,
+                    1 if post.nsfw else 0,
                 ),
             )
             conn.commit()
@@ -207,6 +212,7 @@ class Database:
                 permalink=row["permalink"],
                 source_type=row["source_type"],
                 flair=row["flair"],
+                nsfw=bool(row["nsfw"] or 0),
             )
 
     def get_all_downloaded(self) -> list[PostRecord]:
@@ -232,6 +238,7 @@ class Database:
                         permalink=row["permalink"],
                         source_type=row["source_type"],
                         flair=row["flair"],
+                        nsfw=bool(row["nsfw"] or 0),
                     )
                 )
             return posts
@@ -562,6 +569,7 @@ class Database:
                         permalink=row["permalink"],
                         source_type=row["source_type"],
                         flair=row["flair"],
+                        nsfw=bool(row["nsfw"] or 0),
                     )
                 )
             return posts
@@ -624,6 +632,7 @@ class Database:
                         permalink=row["permalink"],
                         source_type=row["source_type"],
                         flair=row["flair"],
+                        nsfw=bool(row["nsfw"] or 0),
                     )
                 )
             return posts

src/main.py

@@ -199,6 +199,7 @@ def process_post(
             permalink=post.permalink,
             source_type=source_type,
             flair=post.flair,
+            nsfw=post.over_18,
         )
         db.add_post(record)
         db.mark_downloaded(item_id, local_path, file_hash)

src/web/routers/scheduler.py

@@ -293,6 +293,14 @@ async def get_collector_status():
     return collector_status
 
 
+@router.post("/api/collector/clear-error")
+async def clear_collector_error():
+    """Clear the last_error banner after the user dismisses it from the UI."""
+    with collector_lock:
+        collector_status["last_error"] = None
+    return {"message": "cleared"}
+
+
 @router.post("/api/collector/run")
 async def trigger_collector(background_tasks: BackgroundTasks):
     """Trigger the collector to run."""