Add godoc documentation and README with code structure

Add comprehensive godoc comments to all exported types, functions,
and constants throughout the codebase. Create README.md documenting
the project architecture, execution flow, database schema, and
component relationships.

internal/ristypes/ris.go

@@ -58,7 +58,10 @@ type RISLiveMessage struct {
 	Data RISMessage `json:"data"`
 }
 
-// RISMessage represents a message from the RIS Live stream
+// RISMessage represents a BGP update message from the RIPE RIS Live stream.
+// It contains metadata about the BGP session (peer, ASN, host) along with
+// the actual BGP update data including AS path, communities, announcements,
+// and withdrawals.
 type RISMessage struct {
 	Type            string            `json:"type"`
 	Timestamp       float64           `json:"timestamp"`
@@ -80,7 +83,9 @@ type RISMessage struct {
 	Raw             string            `json:"raw,omitempty"`
 }
 
-// RISAnnouncement represents announcement data within a RIS message
+// RISAnnouncement represents a BGP route announcement within a RIS message.
+// It contains the next hop IP address and the list of prefixes being announced
+// via that next hop.
 type RISAnnouncement struct {
 	NextHop  string   `json:"next_hop"`
 	Prefixes []string `json:"prefixes"`