Add DPC community API integration for cross-server faction sharing

[dmccoystephenson]

Overview

Integrate the Medieval Factions plugin with the new DPC community API
(introduced in dansplugins-dot-com#110)
to allow servers running Medieval Factions to publish their faction data
to the DPC community registry. This enables players and server owners to
browse factions from across the community on the DPC website.

The integration is strictly opt-in. Operators receive a toggleable
login reminder and can enable or disable participation at any time via commands.

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Motivation

The DPC website now exposes a POST /api/v1/factions endpoint that accepts
faction data from registered Minecraft servers. Medieval Factions is the
natural first plugin to integrate, as its faction data model maps cleanly
to the API's current schema. Participating server owners will get visibility
on the DPC website — and by optionally including their server IP and Discord
link, they can advertise their server and community directly to DPC visitors
browsing faction data.

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Proposed Scope

Configuration

Add the following to config.yml:

dpc-api:
  enabled: false               # whether this server is opted in to sharing data
  url: "https://dansplugins.com"
  key: ""                      # API key issued by DPC
  login-reminder: true         # whether to show the opt-in reminder to operators on login
  share-server-ip: false       # whether to include the server IP in faction data (enables server advertising on DPC website)
  discord-link: ""             # optional Discord invite link to display on the DPC website alongside faction data

Operator Login Reminder

• When an operator logs in, if dpc-api.enabled: false and dpc-api.login-reminder: true,
  send them a chat message reminding them they can opt in, e.g.:

  [Medieval Factions] Want to share your faction data with the DPC community?
  Run /mf dpc optin to participate, or /mf dpc reminder off to hide this message.
  Tip: run /mf dpc shareip on to advertise your server, or /mf dpc discord <link> to share your Discord.

• The reminder should only show to players with operator-level permission

• The reminder must not appear if dpc-api.enabled: true (already opted in)

Commands

All commands are simple wrappers around setting the corresponding config value:

Command	Effect
/mf dpc optin	Sets dpc-api.enabled: true, saves config, confirms to sender
/mf dpc optout	Sets dpc-api.enabled: false, saves config, confirms to sender
/mf dpc reminder on	Sets dpc-api.login-reminder: true, saves config, confirms to sender
/mf dpc reminder off	Sets dpc-api.login-reminder: false, saves config, confirms to sender
/mf dpc shareip on	Sets dpc-api.share-server-ip: true, saves config, confirms to sender
/mf dpc shareip off	Sets dpc-api.share-server-ip: false, saves config, confirms to sender
/mf dpc discord <link>	Sets dpc-api.discord-link to the provided URL, saves config, confirms to sender
/mf dpc discord clear	Clears dpc-api.discord-link, saves config, confirms to sender

HTTP Client

• Add a lightweight HTTP client service (e.g., using Java's HttpClient or OkHttp)
  to handle communication with the DPC API
• Send requests asynchronously to avoid blocking the server thread

Sync Behavior

• Only runs when dpc-api.enabled: true
• On a configurable interval (e.g., every 10 minutes), or on significant faction
  events (creation, deletion, member join/leave), push the current faction list
  to POST /api/v1/factions
• Payload should conform to the DPC API's faction data model, with serverIp
  and discordLink included only when configured:

{
  "name": "string",
  "serverId": "string",
  "memberCount": 0,
  "description": "string",
  "serverIp": "string or omitted",
  "discordLink": "string or omitted"
}

Data Mapping

Medieval Factions field	DPC API field	Notes
Faction name	name
Server name (from config)	serverId
getMembers().size()	memberCount
Faction description (if present)	description
Server IP (from Bukkit)	serverIp	Only included when share-server-ip: true
dpc-api.discord-link	discordLink	Only included when non-empty

bStats Metrics

Add the following custom metrics to the plugin's bStats chart collection:

Metric name	Type	Description
DPC API Opt-In	Simple pie	Tracks how many servers have dpc-api.enabled: true vs false
DPC API Login Reminder	Simple pie	Tracks how many servers have dpc-api.login-reminder: true vs false
DPC API Share Server IP	Simple pie	Tracks how many servers have dpc-api.share-server-ip: true vs false
DPC API Discord Link Set	Simple pie	Tracks how many servers have a non-empty dpc-api.discord-link

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Acceptance Criteria

• dpc-api.enabled, dpc-api.url, dpc-api.key, dpc-api.login-reminder,
  dpc-api.share-server-ip, and dpc-api.discord-link added to config.yml
  with safe defaults (enabled: false, login-reminder: true,
  share-server-ip: false, discord-link: "")
• Operator login reminder shown when enabled: false and login-reminder: true
• Reminder not shown when enabled: true or login-reminder: false
• Reminder mentions both shareip and discord commands as advertising tips
• /mf dpc optin and /mf dpc optout toggle dpc-api.enabled and save config
• /mf dpc reminder on and /mf dpc reminder off toggle dpc-api.login-reminder and save config
• /mf dpc shareip on and /mf dpc shareip off toggle dpc-api.share-server-ip and save config
• /mf dpc discord <link> sets dpc-api.discord-link and saves config
• /mf dpc discord clear clears dpc-api.discord-link and saves config
• discordLink is included in the faction payload only when discord-link is non-empty
• serverIp is included in the faction payload only when share-server-ip: true
• Factions are only pushed to the API when dpc-api.enabled: true
• X-API-Key header is included on all POST requests
• Sync runs asynchronously and does not block the main server thread
• Failed requests are logged clearly without crashing the plugin
• DPC API Opt-In bStats pie chart registered and reporting
• DPC API Login Reminder bStats pie chart registered and reporting
• DPC API Share Server IP bStats pie chart registered and reporting
• DPC API Discord Link Set bStats pie chart registered and reporting
• README or wiki updated with setup instructions for server owners,
  including notes on the advertising benefits of share-server-ip and discord-link

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Reference

• DPC API PR: dansplugins-dot-com#110
• Endpoint: POST /api/v1/factions
• Auth: X-API-Key header