Add Client Settings documentation section (#612)

* Add Block Inbound Connections documentation to Client settings

Document the previously undocumented "Block Inbound Connections" client
setting (introduced in v0.46.0). Adds a dedicated feature page under
Client > Settings, updates the sidebar navigation, and adds the
--block-inbound flag to the CLI reference.

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

* Move Post-Quantum Cryptography to Client settings and add systray notes

Move the Rosenpass/post-quantum cryptography page from manage/integrations/
to client/ under the new Settings section. Add redirects for the old URL.
Also add systray toggle instructions to both the Quantum-Resistance and
Lazy Connections pages.

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

* Rename post-quantum cryptography page and fix hydration error

Drop the "Enable" prefix from the page title and filename for a cleaner
topic name. Update redirects and navigation. Fix hydration mismatch
caused by a <div> (Button component) nested inside a <p> tag.

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

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

next.config.mjs

@@ -454,7 +454,17 @@ const nextConfig = {
             // documentation redirects for integrations
             {
                 source: '/how-to/enable-post-quantum-cryptography',
-                destination: '/manage/integrations/enable-post-quantum-cryptography',
+                destination: '/client/post-quantum-cryptography',
+                permanent: true,
+            },
+            {
+                source: '/manage/integrations/enable-post-quantum-cryptography',
+                destination: '/client/post-quantum-cryptography',
+                permanent: true,
+            },
+            {
+                source: '/client/enable-post-quantum-cryptography',
+                destination: '/client/post-quantum-cryptography',
                 permanent: true,
             },
             {