feat(events): the public calendar, event pages and participation history (Phase 14a)

The anonymous surface an event was always for: GET /public/events,
/public/events/:slug and /public/events/series/:slug, plus
GET /player/events/history, and the four screens over them.

Four org-lead decisions taken up front: split Phase 14 into 14a (website)
and 14b (the app); add a `listed` flag rather than letting `state` mean both
schedulable and announced; put the `events` capability string in the version
block rather than publishing core as a pseudo-module; and drop "venue" from
the spec rather than adding a field nothing had ever built.

`listed` is announcement, not permission. Publishing is what makes a
definition runnable, so without a separate flag a surprise event would have
to be advertised in order to be allowed to happen. It is a column, a switch
in Phase 13's editor, and three SQL predicates -- never a filter applied
after a read, which works exactly as well until the first caller that forgets.

The public shapes are a projection, and the projection is the security
boundary: nothing is spread, so a column added to event_runs next year does
not ride out through it. The spec, health, cleanup, claims, errors and
member_key are all absent by construction.

The six public event triggers gained `eventUrl` (version 1 -> 2), carrying
?run= because the page lives at the definition's slug while every trigger is
about one occurrence. notify.event-started gained the button, at seedVersion 2.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016wDDVXWMDz82WqE1i969r4

server/test/eventAnnounce.test.js

@@ -283,21 +283,40 @@ test('six are ceilinged authenticated; run.failed is admin on both halves', () =
   }
 })
 
-test('no public event trigger declares a url — there is no page for one to point at yet', () => {
-  // `news.post` shipped an example naming `/news/<slug>`, a path that does not
-  // exist, and the template editor previewed a link that was dead in every mail
-  // it sent. Phase 14 adds the variable alongside the page.
+test('every public event trigger points at the page Phase 14a built, and run.failed at the console', () => {
+  // The inverse of what this asserted from Phase 10 until Phase 14a, and the
+  // inversion is the point: `news.post` shipped an example naming `/news/<slug>`,
+  // a path that did not exist, so the template editor previewed a link that was
+  // dead in every mail it sent. The variable was withheld until there was a page,
+  // and it arrived with it.
   for (const t of eventTriggers()) {
     const urls = t.variables.filter((v) => v.type === 'url')
     if (t.id === 'event.run.failed') {
+      // No `eventUrl` here, deliberately: an admin reading that the machinery
+      // broke wants the steps and the errors, not the storyline.
       assert.deepEqual(urls.map((v) => v.name), ['runUrl'])
       assert.match(urls[0].example, /^\/admin\/events\/runs\//)
     } else {
-      assert.deepEqual(urls, [], `${t.id} must declare no url until Phase 14`)
+      assert.deepEqual(urls.map((v) => v.name), ['eventUrl'], `${t.id}`)
+      // The example has to carry `?run=`, because that is what makes a link in a
+      // mail about last Friday open last Friday rather than next Friday.
+      assert.match(urls[0].example, /^\/site\/events\/[^?]+\?run=/, `${t.id}`)
+      // Optional, so `email.button` drops itself rather than rendering an inert
+      // grey label when the event is not public and there is no page.
+      assert.equal(urls[0].required, false, `${t.id}`)
     }
   }
 })
 
+test('the six public triggers are at version 2 — the url variable is a declaration change', () => {
+  // A variable added to a declaration is a version bump, not a correction: a rule
+  // written against version 1 was written against a payload with no link in it.
+  // `run.failed` gained nothing and stays where it was.
+  for (const t of eventTriggers()) {
+    assert.equal(t.version, t.id === 'event.run.failed' ? 1 : 2, `${t.id}`)
+  }
+})
+
 test('every declared variable carries an example, which is what the editor previews with', () => {
   for (const t of eventTriggers()) {
     for (const v of t.variables) {