S7: OAuth start/options accept system_id; Discord picker QA fixes (server-26#225, #256 #257 #258)

- discord_oauth: POST /discord/oauth/start and GET /options take an optional
  system_id. The system must be the org's own or shared (another org's or
  unknown = 404). Its preferred bot is strict: one that can't connect is a
  404, never a quiet swap to Automatic. No preference = the usual order.
  The picker's "bot for a system" now always sends system_id.
- #257: _channel_state gives a bot whose token Discord rejected its own
  "invalid" state; the picker shows "Radio bot needs replacing" with no
  invite links, instead of "No radio bot".
- #256: Start no longer stays disabled on "Needs fix". It re-checks with
  Discord first (refresh=1) and starts only if the fresh answer allows it.
  "Not a voice channel" still disables Start.
- #258: own tooltip for "Not a voice channel"; "platform admin" -> "DRB
  support"; PreferredBotsCard says plainly that adding your own bot isn't
  self-serve (no support address exists yet, see #47), and a load failure
  gets a plain message + Try again instead of the raw C2 error.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

drb-frontend/lib/discordOAuth.ts

@@ -35,9 +35,9 @@ const post = <T,>(path: string, body: object) => send<T>("POST", path, body);
 export interface OAuthStartRequest {
   /** One of the org's own (BYO) bots, by token_id. */
   token_id?: string;
-  /** The bot marked preferred for this system, when it is a DRB pool bot a platform
-   *  admin pinned (its token_id is not shown to the org). NEEDS S6 to accept
-   *  system_id — until it does, c2-core ignores it and picks Automatic. */
+  /** The bot marked preferred for this system (the org's own system or a shared one),
+   *  including a DRB pool bot a platform admin pinned, whose token_id the org never
+   *  sees. 404 if that bot can't connect servers; c2-core never swaps in another. */
   system_id?: string;
   /** Kept for the plan's node-page entry point: the preferred bot of this node's system. */
   node_id?: string;

drb-frontend/lib/discordPicker.ts

@@ -164,7 +164,7 @@ export function parseC2Error(err: unknown): ParsedC2Error {
 export type BotAccess = "ok" | "denied" | "unknown" | "not_member" | "invalid" | "bad_channel" | "unchecked";
 
 /** Per channel, as c2-core sums it up over the bots that are free. */
-export type ChannelState = "ready" | "needs_fix" | "unknown" | "busy" | "no_bot" | "bad_channel" | "unchecked";
+export type ChannelState = "ready" | "needs_fix" | "unknown" | "busy" | "no_bot" | "invalid" | "bad_channel" | "unchecked";
 
 export interface VoiceCheckBot {
   /** Admin route only. */
@@ -206,7 +206,7 @@ export interface VoiceCheck {
 }
 
 const BOT_ACCESS: readonly string[] = ["ok", "denied", "unknown", "not_member", "invalid", "bad_channel", "unchecked"];
-const CHANNEL_STATES: readonly string[] = ["ready", "needs_fix", "unknown", "busy", "no_bot", "bad_channel", "unchecked"];
+const CHANNEL_STATES: readonly string[] = ["ready", "needs_fix", "unknown", "busy", "no_bot", "invalid", "bad_channel", "unchecked"];
 
 function normBot(b: Record<string, unknown>): VoiceCheckBot {
   const status = (typeof b.status === "string" && BOT_ACCESS.includes(b.status)
@@ -267,6 +267,8 @@ export type ChannelVerdict =
   | { kind: "unknown"; limit: number }
   /** No radio bot is in this server. */
   | { kind: "no_bot"; limit: number }
+  /** A radio bot IS in this server, but Discord rejected its token (server-26#257). No invite: it is already there. */
+  | { kind: "invalid"; limit: number }
   /** The channel exists but is not a voice channel — Start is disabled. */
   | { kind: "not_voice"; limit: number };
 
@@ -283,6 +285,7 @@ export function channelVerdict(c: VoiceCheckChannel | null | undefined): Channel
     case "busy": return { kind: "busy", limit };
     case "unknown": return { kind: "unknown", limit };
     case "no_bot": return { kind: "no_bot", limit };
+    case "invalid": return { kind: "invalid", limit };
     case "bad_channel": return { kind: "not_voice", limit };
     case "unchecked": return null;
     case "needs_fix": return firstDenied ? { kind: "fix", limit, bot: firstDenied } : { kind: "unknown", limit };
@@ -293,6 +296,7 @@ export function channelVerdict(c: VoiceCheckChannel | null | undefined): Channel
   if (free.some((b) => b.ok === null)) return { kind: "unknown", limit };
   if (denied.length) return { kind: "fix", limit, bot: denied[0] };
   if (c.bots.some((b) => b.ok === true)) return { kind: "busy", limit };
+  if (c.bots.some((b) => b.status === "invalid")) return { kind: "invalid", limit };
   return { kind: "unknown", limit };
 }
 
@@ -321,9 +325,9 @@ export function deniedSentence(bot: { name: string; missing: string[]; reason: s
 /** Where in Discord to fix it — c2-core's own sentence when it sent one. */
 export function fixSentence(bot: { name: string; missing: string[]; reason: string | null; fix?: string | null }): string {
   if (bot.fix) return bot.fix;
-  if (bot.reason && /timed out/i.test(bot.reason)) return `In Discord: remove ${bot.name}'s timeout, then Re-check.`;
+  if (bot.reason && /timed out/i.test(bot.reason)) return `In Discord: remove ${bot.name}'s timeout, then try again.`;
   const perms = bot.missing.length ? bot.missing.join(" and ") : "View Channel, Connect and Speak";
-  return `In Discord: Edit Channel → Permissions → add ${bot.name} → allow ${perms}, then Re-check.`;
+  return `In Discord: Edit Channel → Permissions → add ${bot.name} → allow ${perms}, then try again.`;
 }
 
 /** "40s ago" / "3 min ago" for the Re-check footer. */
@@ -355,7 +359,7 @@ export function botLine(b: VoiceCheckBot, channelName?: string | null): { tone:
     case "not_member":
       return { tone: "warn", text: `${b.name}: Discord says it is not in this server — invite it again` };
     case "invalid":
-      return { tone: "bad", text: `${b.name}: its token was rejected by Discord — a platform admin has to replace it` };
+      return { tone: "bad", text: `${b.name}: Discord rejected its token — DRB support has to replace it` };
     case "bad_channel":
       return { tone: "bad", text: `${b.name}: ${channelRef(channelName)} is not a voice channel` };
     case "unchecked":