Fix HAProxy peer entries to include name, address, and port

[Copilot]

HAProxy was discarding the entire peers section because entries were rendered as peer <address> instead of the required peer <name> <address>:<port> format.

Changes

• state/peers.py (new): Add PeersInformation mixin class with HAPROXY_PEER_PORT = 10000 constant and formatted_peer_entries / peer_tcp_port @property methods that pre-render peer lines (e.g. 10-68-79-144 10.68.79.144:10000).
• State dataclasses: IngressRequirersInformation, IngressPerUnitRequirersInformation, and HaproxyRouteRequirersInformation now subclass PeersInformation, exposing the peer formatting as properties.
• src/haproxy.py: reconcile_ingress and reconcile_haproxy_route now read formatted_peer_entries and peer_tcp_port directly from the state objects instead of calling a standalone helper.
• Templates (haproxy_route.cfg.j2, haproxy_ingress.cfg.j2, haproxy_ingress_per_unit.cfg.j2): Add bind *:{{ peer_tcp_port }} and consume pre-rendered peer entries.
• Tests: Add unit tests for the PeersInformation mixin covering IPv4, IPv6, empty input, and port property.

Before/After

# Before (invalid — HAProxy discards this)
peers haproxy_peers
    peer 10.68.79.144

# After
peers haproxy_peers
    bind *:10000
    peer 10-68-79-144 10.68.79.144:10000

[Thanhphan1147]

@copilot This should be a @Property of the charmstate dataclass ( ingress_requirers_information and haproxy_route_requirers_information ). In fact we can make a separate dataclass for this and subclass it in each of the mentioned charmstate dataclass.

[Copilot]

Moved HAPROXY_PEER_PORT and the formatting logic into a PeersInformation mixin class in state/peers.py with formatted_peer_entries and peer_tcp_port as @property methods. IngressRequirersInformation, IngressPerUnitRequirersInformation, and HaproxyRouteRequirersInformation all subclass it. src/haproxy.py now reads the properties from the state objects. See d1ac83e.