docs: add block/mute user relations, emoji-sync CLI, and uid indexes

- Add `/block`, `/mute` endpoints with block/unblock and mute/unmute functionality in `routers/relations.py`, hiding blocked users' content everywhere except their own profile while muting only suppresses notifications
- Introduce `devplace emoji-sync` CLI command to regenerate `static/js/emoji-shortcodes.js` from the emoji library, documented in `CLAUDE.md` and wired in `cli.py`
- Create `get_blocked_uids()` database helper and apply it in `content.py` `load_detail()` to filter blocked users' posts from detail views
- Implement `_uid_index()` and `_drop_index()` helpers in `database.py` for unique uid indexes across tables, with `user_relations` added to `SOFT_DELETE_TABLES`
- Document new routes in `AGENTS.md` and `README.md`, including emoji shortcodes rendering behavior distinct from the emoji picker

tests/e2e/admin/backups/index.py

@@ -4,7 +4,12 @@ import time
 import requests
 from tests.conftest import BASE_URL, login_user
 from devplacepy import config
-from devplacepy.database import get_table, get_primary_admin_uid, refresh_snapshot
+from devplacepy.database import (
+    get_table,
+    get_primary_admin_uid,
+    invalidate_admins_cache,
+    refresh_snapshot,
+)
 from devplacepy.services.backup import store
 from devplacepy.utils import clear_user_cache
 
@@ -29,6 +34,7 @@ def _make_admin():
     row = get_table("users").find_one(username=name)
     get_table("users").update({"uid": row["uid"], "role": "Admin"}, ["uid"])
     clear_user_cache(row["uid"])
+    invalidate_admins_cache()
     return {"email": f"{name}@t.dev", "password": password, "uid": row["uid"]}
 
 
@@ -84,15 +90,20 @@ def test_download_enabled_for_primary_admin(page, app_server):
     for uid in others:
         get_table("users").update({"uid": uid, "role": "Member"}, ["uid"])
         clear_user_cache(uid)
+    invalidate_admins_cache()
     try:
         assert get_primary_admin_uid() == admin["uid"]
         backup_uid = _seed_done_backup(admin["uid"])
         login_user(page, admin)
-        page.goto(f"{BASE_URL}/admin/backups", wait_until="domcontentloaded")
-        row = _row(page, backup_uid)
-        row.wait_for(state="visible", timeout=15000)
-
-        link = row.locator("a.admin-btn:has-text('Download')")
+        link = None
+        for _ in range(20):
+            page.goto(f"{BASE_URL}/admin/backups", wait_until="domcontentloaded")
+            row = _row(page, backup_uid)
+            row.wait_for(state="visible", timeout=15000)
+            link = row.locator("a.admin-btn:has-text('Download')")
+            if link.count() > 0:
+                break
+            time.sleep(0.3)
         link.wait_for(state="visible")
         assert link.get_attribute("href") == f"/admin/backups/{backup_uid}/download"
         assert row.locator("button.admin-btn[title='Not available']").count() == 0