sec05: EN downloads complete (30 files) + SUMMARY at-a-glance + lgdl queue infra

- 30/31 EN candidates downloaded via libgen, all content-verified
  (magic+pages+first-page text); 08b 37-pp fragment discarded
- EN gaps: 04/05/15/16/23 not found (rare academic), 03/14 ia-restricted
- MANIFEST.md: EN sections per item + not-downloadable extended
- 26 cards: Downloads tables w/ EN rows + EN NOT FOUND notes (6 cards)
- SUMMARY.md created (canon v1): at-a-glance table 29 items, EN->RU authors
- tools/lgdl.py: speed-probe + CDN-edge re-draw (per-request get.php
  302s to different storage hosts), connect timeout, stall wipe on first stall
- AGENTS.md: Lesson 9 (EN-queue infra: ads.php throttle, watchdog,
  unbuffered logs, dual-queue trap, AA 403, i2p verdict)

tools/lgdl.py

@@ -36,7 +36,8 @@ BASE = "https://libgen.vg"
 JAR = "/tmp/lgdl_cookies.txt"
 
 
-def curl(url, out=None, referer=None, binary=False, timeout=240, tries=3, extra=None):
+def curl(url, out=None, referer=None, binary=False, timeout=240, tries=3, extra=None,
+         connect_timeout=None):
     cmd = ["curl", "-s", "--fail", "--max-time", str(timeout),
            "-c", JAR, "-b", JAR,
            "-H", "User-Agent: " + UA,
@@ -44,6 +45,8 @@ def curl(url, out=None, referer=None, binary=False, timeout=240, tries=3, extra=
            "-H", "Accept-Language: ru,en;q=0.9",
            "-H", "Referer: " + (referer or BASE + "/"),
            "-L"]
+    if connect_timeout:
+        cmd += ["--connect-timeout", str(connect_timeout)]
     if extra:
         cmd += extra
     if out:
@@ -118,12 +121,15 @@ def download(f_id, out_dir, name, tries=16):
     stall = 0
     for t in range(1, tries + 1):
         card = None
+        print(f"  try {t}: card fetch start")
         for c in range(5):  # card fetch with backoff (libgen DB is flaky)
             try:
                 card = curl(f"{BASE}/ads.php?md5={md5}",
-                            referer=f"{BASE}/file.php?id={f_id}", tries=1)
+                            referer=f"{BASE}/file.php?id={f_id}", tries=1,
+                            timeout=90, connect_timeout=20)
                 break
             except RuntimeError:
+                print(f"  try {t}/{c+1}: card fetch failed — back off")
                 time.sleep(8 * (c + 1))
         if card is None:
             print(f"  try {t}: card fetch failed 5x — back off harder")
@@ -135,11 +141,47 @@ def download(f_id, out_dir, name, tries=16):
             time.sleep(4)
             continue
         url = m.group(1)
+        # speed probe: 6s range fetch on the fresh CDN edge; <15KB/s => this
+        # edge is wedged, re-draw a new get.php link (libgen 302s to different
+        # storage hosts per request)
+        probe_ok = False
+        for p in range(3):
+            try:
+                pr = subprocess.run(["curl", "-s", "--fail", "-o", "/dev/null",
+                                     "-r", "0-300000", "--max-time", "6",
+                                     "--connect-timeout", "10",
+                                     "-H", "User-Agent: " + UA,
+                                     "-H", "Referer: " + f"{BASE}/ads.php?md5={md5}",
+                                     "-w", "%{size_download} %{speed_download}",
+                                     url], capture_output=True, text=True, timeout=20)
+                if pr.returncode == 0:
+                    parts = pr.stdout.split()
+                    spd = float(parts[1]) if len(parts) > 1 else 0
+                    print(f"  try {t}: probe edge {p+1}: {spd/1024:.0f} KB/s")
+                    if spd >= 15 * 1024:
+                        probe_ok = True
+                        break
+            except Exception:
+                pass
+            print(f"  try {t}: edge {p+1} slow/wedged — re-drawing get.php link")
+            time.sleep(3)
+            try:
+                card2 = curl(f"{BASE}/ads.php?md5={md5}",
+                             referer=f"{BASE}/file.php?id={f_id}", tries=1,
+                             timeout=90, connect_timeout=20)
+                m2 = re.search(r'(https?://[^"\']*get\.php\?md5=' + md5 + r'&key=[^"\']+)', card2)
+                if m2:
+                    url = m2.group(1)
+            except RuntimeError:
+                pass
+        if not probe_ok:
+            print(f"  try {t}: all 3 edges slow — waiting out the CDN")
         tmp = out + ".part"
         prev = os.path.getsize(tmp) if os.path.exists(tmp) else 0
+        print(f"  try {t}: data fetch start ({prev}b resumed)")
         try:
             rc = curl(url, out=tmp, referer=f"{BASE}/ads.php?md5={md5}", binary=True,
-                      timeout=3600,
+                      timeout=3600, connect_timeout=30,
                       # abort hung connections: <500B/s for 300s
                       extra=["-C", "-", "--speed-time", "300", "--speed-limit", "500"])
         except RuntimeError as e:
@@ -147,17 +189,13 @@ def download(f_id, out_dir, name, tries=16):
             time.sleep(45)
             continue
         cur = os.path.getsize(tmp) if os.path.exists(tmp) else 0
-        # resume-hang detection: two consecutive zero-progress resumes at the
-        # same offset => this CDN offset is wedged; wipe and start fresh
+        # resume-hang detection: zero-progress resume at the same offset =>
+        # this CDN offset is wedged; wipe and start fresh (first stall is enough)
         if 0 < prev == cur:
-            stall += 1
-            if stall >= 2:
-                print(f"  try {t}: resume stalled 2x at {prev}b — wiping part, fresh start")
-                os.remove(tmp)
-                stall = 0
-                cur = 0
-        else:
+            print(f"  try {t}: resume stalled at {prev}b — wiping part, fresh start")
+            os.remove(tmp)
             stall = 0
+            cur = 0
         data = open(tmp, "rb").read()
         kind = sniff(data)
         ok_size = (size == 0) or (len(data) == size)