feat: the artist picker on Patreon and SubscribeStar too — and the Patreon name is canon (milestone 429)

Operator: "yes add the artist picker to patreon and subscribestar too. but
generally we treat the patreon name as the canon"

- Every add now goes through the panel. On Patreon/SubscribeStar it opens
  on the creator's display name (read only when the panel opens:
  probe?names=1), searches FC's artists with it, and auto-picks a match.
  An untouched URL handle sends no name, so the server still resolves it.
- Patreon is canon: joining a Patreon source to an artist known by another
  name offers "Rename “x” to the Patreon name “X”", ticked by default.
  quick-add's use_platform_name renames server-side from the name it reads
  itself; name only, the slug never moves (#130); never to a URL handle when
  the name can't be read; ignored on SubscribeStar and Discord.
- _platform_display_name returns None rather than the handle, bounded by the
  same 6s lookup budget as Discord's names.
- panelDefaults / addRequest / renameOffer replace the Discord-only helpers.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LVjrnpQjRgHdvq95rASoiR

extension/content/content-script.js

@@ -84,13 +84,14 @@
       await openArtist(btn, probe.artist?.slug);
       return;
     }
-    // A Discord URL names a channel, not a creator — ask which artist.
-    if (probe?.platform === 'discord') {
-      if (document.getElementById('fc-discord-panel')) closePanel();
-      else openDiscordPanel(probe);
+    // Every add goes through the panel, so the operator can match the page to
+    // an artist FabledCurator already has (the same creator is often spelled
+    // differently per platform) instead of minting a duplicate.
+    if (document.getElementById('fc-add-panel')) {
+      closePanel();
       return;
     }
-    await add(btn, { url: window.location.href });
+    await openAddPanel(btn, probe);
   }
 
   async function openArtist(btn, slug) {
@@ -121,7 +122,8 @@
         return false;
       }
       const verb = r.created_source ? 'Added to' : 'Already a source for';
-      showToast(`${verb} ${r.artist?.name || 'artist'} (${r.source?.platform || ''})`, 'success');
+      const renamed = r.renamed_from ? ` — renamed from “${r.renamed_from}”` : '';
+      showToast(`${verb} ${r.artist?.name || 'artist'} (${r.source?.platform || ''})${renamed}`, 'success');
       // Re-probe so the chip flips green without waiting for a navigation.
       evaluate();
       return true;
@@ -134,10 +136,13 @@
     }
   }
 
-  // ---- Discord Add panel ----
-  // Where: this channel or the whole server. Who: the suggested artist, one
-  // found by search, or a new one by name. Built with createElement only —
-  // server, channel and artist names are other people's text.
+  // ---- Add panel ----
+  // Who: the suggested artist, one found by search, or a new one by name —
+  // on every platform. Where (Discord only): this channel or the whole
+  // server. On Patreon, joining an artist known by another name offers the
+  // Patreon name, which the operator treats as canon. Built with
+  // createElement only — server, channel and artist names are other people's
+  // text.
 
   function el(tag, props = {}, children = []) {
     const node = document.createElement(tag);
@@ -150,13 +155,35 @@
   }
 
   function closePanel() {
-    document.getElementById('fc-discord-panel')?.remove();
+    document.getElementById('fc-add-panel')?.remove();
   }
 
-  function openDiscordPanel(probe) {
+  async function openAddPanel(btn, probe) {
     closePanel();
+    const platformName = PLATFORMS[probe.platform]?.name || probe.platform;
+    // Discord's probe already carries its names. Patreon/SubscribeStar read the
+    // creator's display name only now, when the panel needs it — a request to
+    // the platform the chip's own probe deliberately doesn't make.
+    if (probe.platform !== 'discord') {
+      const original = btn.textContent;
+      btn.disabled = true;
+      btn.textContent = `Reading the ${platformName} name…`;
+      try {
+        const named = await browser.runtime.sendMessage({
+          type: 'PROBE_SOURCE', url: window.location.href, names: true,
+        });
+        if (named && !named.error) probe = named;
+      } catch { /* fall back to the chip's probe: the URL handle */ }
+      btn.disabled = false;
+      btn.textContent = original;
+      if (probe.state === 'source_match') {
+        renderButton(probe);
+        return;
+      }
+    }
     const d = probe.discord || {};
-    const choice = discordPanelDefaults(probe);
+    const discord = probe.platform === 'discord';
+    const choice = panelDefaults(probe, window.location.href);
 
     const scopeRow = (value, label, disabled) => {
       const input = el('input', {
@@ -186,14 +213,27 @@
     const addBtn = el('button', { class: 'fc-panel__btn fc-panel__btn--primary', text: 'Add' });
     const cancelBtn = el('button', { class: 'fc-panel__btn', text: 'Cancel' });
 
-    const panel = el('div', { id: 'fc-discord-panel', class: 'fc-panel' }, [
-      el('div', { class: 'fc-panel__title', text: 'Add Discord source' }),
-      el('div', { class: 'fc-panel__sub', text: serverLabel(d) }),
-      el('div', { class: 'fc-panel__label', text: 'Follow' }),
-      scopeRow('channel', d.channel_id ? channelLabel(d) : 'this channel', !d.channel_id),
-      scopeRow('server', `Every channel in ${serverLabel(d)}`, false),
+    // Patreon is canon: joining an artist known by another name takes the
+    // Patreon name unless this is unticked. Shown only when it would rename.
+    const renameBox = el('input', { type: 'checkbox', checked: choice.adoptPlatformName });
+    const renameText = el('span');
+    const renameRow = el('label', { class: 'fc-panel__radio fc-panel__rename' }, [renameBox, renameText]);
+    renameBox.addEventListener('change', () => { choice.adoptPlatformName = renameBox.checked; refresh(); });
+
+    const sub = discord
+      ? serverLabel(d)
+      : [probe.display_name, probe.slug].filter(Boolean).filter((v, i, a) => a.indexOf(v) === i).join(' · ');
+    const panel = el('div', { id: 'fc-add-panel', class: 'fc-panel' }, [
+      el('div', { class: 'fc-panel__title', text: `Add ${platformName} source` }),
+      el('div', { class: 'fc-panel__sub', text: sub }),
+      ...(discord ? [
+        el('div', { class: 'fc-panel__label', text: 'Follow' }),
+        scopeRow('channel', d.channel_id ? channelLabel(d) : 'this channel', !d.channel_id),
+        scopeRow('server', `Every channel in ${serverLabel(d)}`, false),
+      ] : []),
       el('div', { class: 'fc-panel__label', text: 'Artist' }),
       el('div', { class: 'fc-panel__combo' }, [nameInput, results]),
+      renameRow,
       hint,
       el('div', { class: 'fc-panel__actions' }, [cancelBtn, addBtn]),
     ]);
@@ -205,12 +245,16 @@
     let listOpen = false;
 
     function refresh() {
-      const req = discordAddRequest(choice);
+      const req = addRequest(choice);
       addBtn.disabled = !req;
       if (!req) hint.textContent = 'Pick an artist or type a name.';
       else if (req.artistId != null) hint.textContent = `✓ Connects to ${choice.artist.name}, already in FabledCurator.`;
-      else hint.textContent = `Creates a new artist “${req.artistName}”.`;
+      else if (req.artistName) hint.textContent = `Creates a new artist “${req.artistName}”.`;
+      else hint.textContent = `Creates a new artist, named from the ${platformName} page.`;
       hint.classList.toggle('fc-panel__hint--match', !!req && req.artistId != null);
+      const offer = renameOffer(choice);
+      renameRow.hidden = !offer;
+      if (offer) renameText.textContent = `Rename “${offer.from}” to the Patreon name “${offer.to}”`;
     }
 
     function pick(artist) {
@@ -346,7 +390,7 @@
 
     cancelBtn.addEventListener('click', closePanel);
     addBtn.addEventListener('click', async () => {
-      const req = discordAddRequest(choice);
+      const req = addRequest(choice);
       if (!req) return;
       const btn = document.getElementById('fc-add-source-btn');
       addBtn.disabled = true;