docs: add Voice & Style guide and rewrite docs pages to match

Add a Voice & Style section to the docs authoring guide, then bring every
docs page in line with it: lead with the task, add success signals to
procedures, explain jargon on first use, keep bullet casing consistent,
and link out to Troubleshooting where steps can fail.

Applied across English source and all localized versions (uk, zh-cn, es,
pt-br, ko, pl).

packages/docs/content/docs/tunnels.mdx

@@ -5,7 +5,7 @@ description: Expose OpenChamber safely for remote and mobile access.
 
 # Tunnels
 
-Use `openchamber tunnel` to expose a running OpenChamber instance.
+A tunnel is a public link to your OpenChamber, so you can reach it from your phone or another network. Use `openchamber tunnel` to create one for a running instance.
 
 ## Quick start (Cloudflare quick mode)
 
@@ -27,6 +27,8 @@ openchamber tunnel start --provider cloudflare --mode quick
 openchamber tunnel status
 ```
 
+When the tunnel is up, `status` shows a public URL. Open it, or scan the QR code, to reach OpenChamber from anywhere.
+
 By default, OpenChamber prints a QR code in interactive TTY sessions. Use `--qr` to force QR output, or `--no-qr` to disable it.
 
 ## Managed modes
@@ -75,3 +77,7 @@ openchamber tunnel stop --port 3000
 - one active tunnel per OpenChamber instance (port)
 - starting a new mode/provider on same instance replaces previous tunnel
 - generating a new connect link revokes previous unused one
+
+## Related
+
+- [Troubleshooting](/troubleshooting/) — if the tunnel link doesn't work