docs(troubleshooting): add filtered logread recipe + cross-link from Curl 7

Add the loopback-filtered command `logread -f | grep -v '127.0.0.1'` to
DEVICE-LOGGING.md's Pro-Tip section with a one-line rationale (strips
the speaker's in-device localhost chatter so cloud/AfterTouch attempts
are readable). Cross-link from the new Curl 7 entry in TROUBLESHOOTING
so users hitting that symptom find the SSH/logread how-to.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/DEVICE-LOGGING.md

@@ -48,6 +48,12 @@ logread -f | grep -Ei '(marge|preset)'
 ```
 This is particularly useful for debugging preset synchronization and service redirection issues.
 
+For HTTPS / connection-refused debugging (e.g. `Curl 7, http 0`), drop the speaker's loopback chatter so only outbound calls remain visible:
+```bash
+logread -f | grep -v '127.0.0.1'
+```
+The speaker generates a steady stream of localhost-to-localhost HTTP traffic between its internal services; filtering it out makes the actual cloud / AfterTouch attempts (the ones that matter when diagnosing redirect or TLS issues) easy to read in real time.
+
 ---
 
 ## 2. Traffic Logging & Interception

docs/guides/TROUBLESHOOTING.md

@@ -109,7 +109,7 @@ iperf3 -c 192.168.1.1  # If iperf server available
 
 **Symptoms:**
 
-In the speaker's log (`logread -f` over SSH):
+In the speaker's log (see [DEVICE-LOGGING.md](../DEVICE-LOGGING.md#1-accessing-system-logs-requires-root) for the SSH/`logread` setup — the filtered command `logread -f | grep -v '127.0.0.1'` is what you want here):
 
 ```
 SimpleURLFetcher: retry needed, Curl 7, http 0