httpx2 raises on 3xx responses, so the vision stage's image download
failed for posts whose attachments are served via Mastodon's
media_proxy redirect URLs. Create the download client with
follow_redirects=True, and guess the MIME type from the post-redirect
final URL so proxied PNG/WebP/GIF attachments are labelled correctly.

Closes #105

@@ -75,3 +75,3 @@
     now = datetime.now(UTC)
     headers = {"User-Agent": "fenliu-ai/0.1"}
-    async with httpx2.AsyncClient(timeout=180, headers=headers) as http:
+    async with httpx2.AsyncClient(timeout=180, headers=headers, follow_redirects=True) as http:

@@ -10,3 +10,4 @@
 
 ---
 
+Some Mastodon attachments are served through a redirecting `media_proxy` URL rather than a direct file link. The AI vision stage's image downloader treated those redirects as errors, so posts with proxy-served media never received a vision verdict and had to be reviewed by hand. It now follows the redirect to the real file — and reads the image type from the final URL, so proxied PNG/WebP/GIF attachments are labelled correctly instead of always assumed JPEG.

@@ -285,3 +285,3 @@
 
     def decorator(func: Callable) -> Callable:
-        if asyncio.iscoroutinefunction(func):
+        if inspect.iscoroutinefunction(func):

@@ -10,3 +10,4 @@
 
 ---
 
+Some Mastodon attachments are served through a redirecting `media_proxy` URL rather than a direct file link. The AI vision stage's image downloader treated those redirects as errors, so posts with proxy-served media never received a vision verdict and had to be reviewed by hand. It now follows the redirect to the real file — and reads the image type from the final URL, so proxied PNG/WebP/GIF attachments are labelled correctly instead of always assumed JPEG.

@@ -6,3 +6,3 @@
 
-import asyncio
 import functools
+import inspect

@@ -138,0 +166,4 @@
+    with (
+        patch("fenliu.services.ai_pipeline.text_classifier", return_value=text),
+        patch("fenliu.services.ai_pipeline.vision_classifier", return_value=vision),
+        patch("fenliu.services.ai_pipeline.httpx2", new=SimpleNamespace(AsyncClient=TransportInjectedClient)),

@@ -5,3 +5,3 @@
 fenliu 3.0.0
 
--
+- Fixed: AI vision now follows media-proxy redirects, so proxy-served attachments get classified instead of stalling as pending.

@@ -10,3 +10,4 @@
 
 ---
 
+Some Mastodon attachments are served through a redirecting `media_proxy` URL rather than a direct file link. The AI vision stage's image downloader treated those redirects as errors, so posts with proxy-served media never received a vision verdict and had to be reviewed by hand. It now follows the redirect to the real file — and reads the image type from the final URL, so proxied PNG/WebP/GIF attachments are labelled correctly instead of always falling back to image/jpeg.

@@ -10,3 +10,4 @@
 
 ---
 
+Some Mastodon attachments are served through a redirecting `media_proxy` URL rather than a direct file link. The AI vision stage's image downloader treated those redirects as errors, so posts with proxy-served media never received a vision verdict and had to be reviewed by hand. It now follows the redirect to the real file and reads the image type from the final URL, so proxied PNG/WebP/GIF attachments are labelled correctly instead of always falling back to `image/jpeg`.

@@ -5,3 +5,3 @@
 fenliu 3.0.0
 
--
+- Fixed: AI vision now follows `media_proxy` redirects, so proxy-served attachments get classified instead of stalling as pending.