Add .ics calendar feed support

doot reads Google Calendar through a service account, by calendar ID. That
cannot consume an .ics URL, and it cannot see a calendar subscribed to inside a
personal Google account either, because Google does not allow re-sharing a
subscribed calendar. Published schedules — sports fixtures, school terms, bin
collections — are distributed almost exclusively as .ics, so none of them could
be added at all.

Feeds are now fetched on the normal calendar refresh and merged into
calendar_events alongside Google events, so the timeline, widget and everything
downstream keep seeing one list and needed no changes.

Failure handling is deliberately asymmetric. A Google error is still returned as
an error, unchanged, so an outage there surfaces. A single failing feed is
recorded against that feed and skipped, because one dead URL should not take the
whole calendar down — and last_error is shown in settings, since a feed that has
quietly stopped resolving otherwise looks identical to a team with no games
left.

The parser handles what real feeds actually contain: line unfolding, CRLF and
LF, UTC / TZID / VALUE=DATE times, and escaped text. Two details worth naming:
a TZID time is wall-clock in that zone, and reading it as UTC would put a 1:15pm
Pacific kickoff on the timeline at 1:15pm local — wrong by the offset but
entirely plausible-looking. And non-calendar content is a hard error rather than
zero events, because an HTML error page from a moved feed URL is the common
failure and "no events" reads as success.

RRULE is deliberately unsupported: every schedule feed this targets expands
recurrence itself, one VEVENT per fixture, and a correct expansion is a large
amount of subtle code. A recurring event appears once rather than wrongly.

Settings gains an add/enable/disable/remove UI. webcal:// links are accepted and
rewritten, since that is how feeds are usually advertised.

16 parser tests, 5 store tests. Verified against the real Seattle Seahawks feed:
21 events, all with valid times.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018AwnALZL6bD4VBtATDVv3B

1 files changed, 43 insertions, 0 deletions

diff --git a/web/templates/partials/ics-feeds.html b/web/templates/partials/ics-feeds.html
new file mode 100644
index 0000000..4ee1ad6
--- /dev/null
+++ b/web/templates/partials/ics-feeds.html
@@ -0,0 +1,43 @@
+{{define "ics-feed-list"}}
+<div id="ics-feed-list" class="space-y-3">
+    {{if .Feeds}}
+    {{range .Feeds}}
+    <div class="flex flex-wrap items-center gap-3 p-3 rounded-lg border border-white/10 bg-white/5">
+        <div class="flex-1 min-w-0">
+            <div class="flex items-center gap-2">
+                <span class="text-white {{if not .Enabled}}opacity-50{{end}}">{{.Name}}</span>
+                {{if not .Enabled}}<span class="text-xs text-white/40">(off)</span>{{end}}
+            </div>
+            <div class="text-xs text-white/40 truncate">{{.URL}}</div>
+            <div class="text-xs mt-1 {{if .LastError}}text-red-400{{else}}text-white/40{{end}}">
+                {{if .LastError}}
+                    Failed: {{.LastError}}
+                {{else}}
+                    {{.EventCount}} events · last checked {{.LastFetched}}
+                {{end}}
+            </div>
+        </div>
+        <form hx-post="/settings/ics-feeds/{{.ID}}/toggle" hx-target="#ics-feed-list" hx-swap="outerHTML">
+            <input type="hidden" name="enabled" value="{{if .Enabled}}false{{else}}true{{end}}">
+            <button type="submit" class="text-xs px-3 py-1.5 rounded-lg bg-white/10 hover:bg-white/20 text-white/70 hover:text-white transition-colors">
+                {{if .Enabled}}Disable{{else}}Enable{{end}}
+            </button>
+        </form>
+        <button class="text-xs px-3 py-1.5 rounded-lg border border-red-500/30 text-red-400 hover:bg-red-500/10 transition-colors"
+                hx-delete="/settings/ics-feeds/{{.ID}}"
+                hx-target="#ics-feed-list"
+                hx-swap="outerHTML"
+                hx-confirm="Remove {{.Name}}? Its events disappear from the timeline.">
+            Remove
+        </button>
+    </div>
+    {{end}}
+    {{else}}
+    <p class="text-sm text-white/40">
+        No calendar feeds yet. Paste an .ics or webcal:// link below — published
+        schedules (sports fixtures, school terms, bin collections) are almost
+        always distributed this way.
+    </p>
+    {{end}}
+</div>
+{{end}}