feat: two-way sync between support tickets and Gitea issues (v0.63.0)

Outbound (already existed one-way: ticket create -> Gitea issue) now
also mirrors status changes: closing/reopening a ticket in the admin
UI closes/reopens the linked Gitea issue, and replies posted from
Epicure (by the ticket owner or an admin) post as a comment on the
issue. Captures and stores the Gitea issue number at creation time
to address these follow-up calls without re-parsing the issue URL.

Inbound: new webhook receiver at /api/webhooks/gitea, verified via
HMAC-SHA256 signature (X-Gitea-Signature) with a configurable
GITEA_WEBHOOK_SECRET site setting, deduped by delivery id the same
way the existing Stripe receiver dedupes events. Handles "issues"
(closed/reopened -> ticket status) and "issue_comment" (created ->
appends to the ticket's comment thread), skipping comments Epicura
already posted itself (matched by Gitea comment id) to avoid loops.

New support_ticket_comments table backs a lightweight conversation
thread on both the user-facing support page and the admin support
manager, each comment tagged by author (user/admin/gitea).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/app/api/v1/support/route.ts

@@ -66,7 +66,7 @@ export async function POST(req: NextRequest) {
   const id = crypto.randomUUID();
   const now = new Date();
 
-  const { url: giteaIssueUrl, error: giteaError } = await createGiteaIssue({
+  const { url: giteaIssueUrl, number: giteaIssueNumber, error: giteaError } = await createGiteaIssue({
     type,
     title,
     body: buildGiteaIssueBody({ description, userId: session!.user.id, attachments }),
@@ -80,6 +80,7 @@ export async function POST(req: NextRequest) {
     description,
     status: "open",
     giteaIssueUrl,
+    giteaIssueNumber,
     giteaError,
     createdAt: now,
     updatedAt: now,