feat(post): add client tag and remove reset button

Client tag:
- Add ["client", "grimoire"] tag to all published events
- Added to both handlePublish and retryRelay functions
- Identifies posts as coming from Grimoire client

UI cleanup:
- Remove reset button from relay selection UI
- Relay selection persists across sessions via draft storage
- Simplify header to just show relay count
- Remove unused RotateCcw icon import

Tag generation order (final):
1. p tags (mentions)
2. e tags (event references)
3. a tags (address references)
4. client tag (grimoire)
5. emoji tags (NIP-30)
6. imeta tags (NIP-92)

src/components/PostViewer.tsx

@@ -1,5 +1,5 @@
 import { useState, useRef, useCallback, useMemo, useEffect } from "react";
-import { Paperclip, Send, Loader2, Check, X, RotateCcw } from "lucide-react";
+import { Paperclip, Send, Loader2, Check, X } from "lucide-react";
 import { toast } from "sonner";
 import { Button } from "./ui/button";
 import { Checkbox } from "./ui/checkbox";
@@ -201,6 +201,9 @@ export function PostViewer() {
           tags.push(["a", `${addr.kind}:${addr.pubkey}:${addr.identifier}`]);
         }
 
+        // Add client tag
+        tags.push(["client", "grimoire"]);
+
         // Add emoji tags
         for (const emoji of serialized.emojiTags) {
           tags.push(["emoji", emoji.shortcode, emoji.url]);
@@ -323,6 +326,9 @@ export function PostViewer() {
           tags.push(["a", `${addr.kind}:${addr.pubkey}:${addr.identifier}`]);
         }
 
+        // Add client tag
+        tags.push(["client", "grimoire"]);
+
         // Add emoji tags
         for (const emoji of emojiTags) {
           tags.push(["emoji", emoji.shortcode, emoji.url]);
@@ -506,18 +512,6 @@ export function PostViewer() {
           <span className="text-sm text-muted-foreground">
             Relays ({selectedRelays.size} selected)
           </span>
-          {writeRelays.length > 0 && (
-            <Button
-              variant="ghost"
-              size="icon"
-              onClick={updateRelayStates}
-              disabled={isPublishing}
-              className="h-6 w-6"
-              title="Reset relay selection"
-            >
-              <RotateCcw className="h-3 w-3" />
-            </Button>
-          )}
         </div>
 
         {writeRelays.length === 0 ? (