feat(admin): manual account blocking (suspensions)

Operator-driven hard block, the counterpart to the soft high-rate flag: permanent or until a date, with an optional reason chosen from an editable en+ru picklist (snapshotted onto the block). A block forfeits the player's active games (opponent wins, as a resignation) and cancels their open matchmaking games. A backend gate refuses a blocked account on every /api/v1/user/* route except the block-status probe with 403 account_blocked, which threads through the gateway as the Execute result_code; the UI surfaces it as a terminal blocked screen and stops all push/poll. Temporary blocks self-expire; the operator can unblock at any time (lost games stay lost). Sessions are not revoked, so the blocked client can still reach the exempt block-status endpoint.

Backend: migration 00003 (account_suspensions + suspension_reasons) + jet regen; account suspension store; game.ForfeitAllForAccount; requireNotSuspended gate + block-status endpoint; admin console block/unblock + Reasons CRUD. Wire: fbs BlockStatus + account.block_status gateway op. UI: blocked screen, app state, transport/codec, i18n. Docs: ARCHITECTURE, FUNCTIONAL(+ru), PRERELEASE (AB).

backend/internal/adminconsole/templates/layout.gohtml

@@ -18,6 +18,7 @@
     <a href="/_gm/complaints"{{if eq .ActiveNav "complaints"}} class="active"{{end}}>Complaints</a>
     <a href="/_gm/messages"{{if eq .ActiveNav "messages"}} class="active"{{end}}>Messages</a>
     <a href="/_gm/throttled"{{if eq .ActiveNav "throttled"}} class="active"{{end}}>Throttled</a>
+    <a href="/_gm/reasons"{{if eq .ActiveNav "reasons"}} class="active"{{end}}>Reasons</a>
     <a href="/_gm/dictionary"{{if eq .ActiveNav "dictionary"}} class="active"{{end}}>Dictionary</a>
     <a href="/_gm/broadcast"{{if eq .ActiveNav "broadcast"}} class="active"{{end}}>Broadcast</a>
     <a href="/_gm/grafana/">Grafana ↗</a>

backend/internal/adminconsole/templates/pages/reasons.gohtml

@@ -0,0 +1,27 @@
+{{define "content" -}}
+<h1>Suspension reasons</h1>
+{{with .Data}}
+<p class="note">Reasons offered when blocking a user; each is shown to the blocked player in their own language. Editing or deleting a reason does not change a reason already shown to a currently-blocked player (blocks snapshot the text).</p>
+<section class="panel"><h2>Add reason</h2>
+<form class="form col" method="post" action="/_gm/reasons">
+<label>English <input type="text" name="text_en" required></label>
+<label>Russian <input type="text" name="text_ru" required></label>
+<div><button type="submit">Add</button></div>
+</form>
+</section>
+<section class="panel"><h2>Existing reasons</h2>
+{{range .Items}}
+<div class="row">
+<form class="form" method="post" action="/_gm/reasons/{{.ID}}/update">
+<input type="text" name="text_en" value="{{.TextEn}}" aria-label="English" required>
+<input type="text" name="text_ru" value="{{.TextRu}}" aria-label="Russian" required>
+<button type="submit">Save</button>
+</form>
+<form class="form" method="post" action="/_gm/reasons/{{.ID}}/delete">
+<button type="submit">Delete</button>
+</form>
+</div>
+{{else}}<p class="note">no reasons yet</p>{{end}}
+</section>
+{{end}}
+{{- end}}

backend/internal/adminconsole/templates/pages/user_detail.gohtml

@@ -34,6 +34,35 @@
 {{else}}<p class="note">no statistics</p>{{end}}
 </section>
 </div>
+<section class="panel"><h2>Account block</h2>
+{{$uid := .ID}}
+{{with .Suspension}}{{if .Blocked}}
+<ul class="kv">
+<li><b>Status</b> <span class="warn">{{if .Permanent}}blocked (permanent){{else}}blocked until {{.Until}} (UTC){{end}}</span></li>
+{{if .BlockedAt}}<li><b>Since</b> {{.BlockedAt}}</li>{{end}}
+{{if .ReasonEn}}<li><b>Reason</b> {{.ReasonEn}} / {{.ReasonRu}}</li>{{end}}
+</ul>
+<form class="form" method="post" action="/_gm/users/{{$uid}}/unblock">
+<button type="submit">Unblock</button>
+</form>
+{{else}}<p class="note">not blocked</p>{{end}}{{end}}
+<form class="form col" method="post" action="/_gm/users/{{.ID}}/block">
+<label>Duration <select name="duration">
+<option value="permanent">permanent</option>
+<option value="1d">1 day</option>
+<option value="3d">3 days</option>
+<option value="1w">1 week</option>
+<option value="1m">1 month</option>
+<option value="custom">custom date (UTC)</option>
+</select></label>
+<label>Custom until (UTC; used when duration is "custom") <input type="datetime-local" name="until"></label>
+<label>Reason <select name="reason">
+<option value="">&mdash; none &mdash;</option>
+{{range .Reasons}}<option value="{{.ID}}">{{.TextEn}}</option>{{end}}
+</select></label>
+<div><button type="submit">{{if .Suspension.Blocked}}Re-block{{else}}Block{{end}}</button></div>
+</form>
+</section>
 {{if .MoveChart}}
 <section class="panel"><h2>Move timing</h2>
 <p class="note">Think time per move number across all games — <span class="lg lg-min">min</span> · <span class="lg lg-avg">mean</span> · <span class="lg lg-max">max</span>.</p>