refactor: rename Personal Pro to Skipper and Team Pro to Admiral (#256)

Align paid tier names with Sencho's nautical identity. Internal variant
values ('personal'/'team') remain unchanged in code, database, and
Lemon Squeezy integration — only user-facing display names updated.

- Backend: requireTeamPro → requireAdmiral, TEAM_PRO_REQUIRED → ADMIRAL_REQUIRED
- Frontend: TeamProGate.tsx → AdmiralGate.tsx, TierBadge labels updated
- Website: PricingSection tier names and nautical descriptions
- Docs: all 11 affected pages renamed, nautical footnote added to licensing

docs/getting-started/configuration.mdx

@@ -29,7 +29,7 @@ When you point `COMPOSE_DIR` at a directory, Sencho expects each stack to live i
 
 ## SSO environment variables
 
-If you use SSO (Team Pro), configure your identity providers via environment variables:
+If you use SSO (Admiral), configure your identity providers via environment variables:
 
 | Variable | Description |
 |----------|-------------|

docs/getting-started/sso-quickstart.mdx

@@ -4,7 +4,7 @@ description: Step-by-step instructions for connecting Sencho to your identity pr
 ---
 
 <Note>
-  SSO requires a Sencho **Team Pro** license. You can configure SSO via environment variables (shown below) or from the Settings UI after first boot.
+  SSO requires a Sencho **Admiral** license. You can configure SSO via environment variables (shown below) or from the Settings UI after first boot.
 </Note>
 
 ## Google OIDC