feat: add Immich API client and photo proxy routes

Implements ImmichClient with list_albums, get_album, get_thumbnail,
get_original methods; wraps connection errors as ConnectionError.
Adds /proxy/thumb/<asset_id> and /proxy/original/<asset_id> Flask routes.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

services/travel-memories/app/immich.py

@@ -0,0 +1,30 @@
+import requests
+
+
+class ImmichClient:
+    def __init__(self, base_url: str, api_key: str):
+        self.base_url = base_url.rstrip("/")
+        self.headers = {"Authorization": f"Bearer {api_key}"}
+
+    def _get(self, path: str, **kwargs):
+        try:
+            r = requests.get(f"{self.base_url}{path}",
+                             headers=self.headers, timeout=10, **kwargs)
+            r.raise_for_status()
+            return r
+        except requests.exceptions.ConnectionError as e:
+            raise ConnectionError(f"Cannot reach Immich: {e}") from e
+
+    def list_albums(self) -> list:
+        return self._get("/api/albums").json()
+
+    def get_album(self, album_id: str) -> dict:
+        return self._get(f"/api/albums/{album_id}",
+                         params={"withoutAssets": "false"}).json()
+
+    def get_thumbnail(self, asset_id: str) -> bytes:
+        return self._get(f"/api/assets/{asset_id}/thumbnail",
+                         params={"size": "preview"}).content
+
+    def get_original(self, asset_id: str) -> bytes:
+        return self._get(f"/api/assets/{asset_id}/original").content

services/travel-memories/app/routes/proxy.py

@@ -1,3 +1,29 @@
-from flask import Blueprint
+from flask import Blueprint, current_app, Response, abort
+from app.immich import ImmichClient
 
 bp = Blueprint("proxy", __name__)
+
+
+def _client() -> ImmichClient:
+    return ImmichClient(
+        base_url=current_app.config["IMMICH_URL"],
+        api_key=current_app.config["IMMICH_API_KEY"],
+    )
+
+
+@bp.get("/proxy/thumb/<asset_id>")
+def thumb(asset_id):
+    try:
+        data = _client().get_thumbnail(asset_id)
+    except ConnectionError:
+        abort(502)
+    return Response(data, content_type="image/jpeg")
+
+
+@bp.get("/proxy/original/<asset_id>")
+def original(asset_id):
+    try:
+        data = _client().get_original(asset_id)
+    except ConnectionError:
+        abort(502)
+    return Response(data, content_type="image/jpeg")