fix: replace per-path proxy with cookie-based catch-all routing

The /session/{id} URL prefix collided with OpenCode's internal
/session/{slug} SPA routes, causing a blank page. Now /c/{id} is
a thin entry point that sets a session cookie and redirects to /,
where the SPA loads at root with its router working correctly.

This also replaces ~50 individual per-path proxy route handlers
with a single /{path:path} catch-all, and simplifies the Caddyfile
from ~180 lines to ~17.

nginx/Caddyfile

@@ -2,187 +2,16 @@
 # Using HTTP for local development (no SSL warnings)
 
 # Main web interface - HTTP only for development
-http://localhost {
-    # API endpoints for session management
+:80 {
+    # API endpoints for session management (strip /api prefix)
     handle /api/* {
         uri strip_prefix /api
         reverse_proxy session-manager:8000
     }
 
-    # OpenCode internal session API (without session_id in path)
-    # Must be BEFORE /session/{session_id}* to match first
-    handle /session {
+    # Everything else goes to session-manager (handles /c/{id} entry
+    # point and cookie-based proxy to OpenCode containers)
+    handle {
         reverse_proxy session-manager:8000
     }
-
-    # Session-specific routing - proxy to session manager for dynamic routing
-    handle /session/{session_id}* {
-        reverse_proxy session-manager:8000
-    }
-
-    # OpenCode SPA runtime requests - route based on session cookie
-    handle /global/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /assets/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /provider/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /provider {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /project {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /path {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /find/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /file {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /file/* {
-        reverse_proxy session-manager:8000
-    }
-
-    # Additional OpenCode API endpoints for root-path operation
-    handle /agent {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /agent/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /config {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /config/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /model {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /model/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /thread/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /chat/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /tree {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /tree/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /conversation {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /conversation/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /project/* {
-        reverse_proxy session-manager:8000
-    }
-
-    # OpenCode communication endpoints for message sending
-    handle /command {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /command/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /mcp {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /mcp/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /lsp {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /lsp/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /vcs {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /vcs/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /permission {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /permission/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /question {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /question/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /event {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /event/* {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /status {
-        reverse_proxy session-manager:8000
-    }
-
-    handle /status/* {
-        reverse_proxy session-manager:8000
-    }
-
-    # Health check
-    handle /health {
-        reverse_proxy session-manager:8000
-    }
-
-    # Static files and main interface (fallback)
-    handle /* {
-        try_files {path} {path}/ /index.html
-        file_server
-    }
-}
+}