feat: steadier live updates and notices for public proposals

- The web pings the live connection, reconnects when it goes quiet and
  reloads what each screen shows after reconnecting.
- Dropping a card on a column it cannot go to puts it back.
- Owners and admins get a notice when a proposal arrives.
- The proposal limit lives in Redis, so it holds across instances.
- REST tells whether I voted; pasted images leave the attachment list.
- Deleting a project removes its Git integration; no lint warnings left.
- Reactions and the blocked badge are components of their own.
- Docs: what is done and what is left (chapter 10), Word and PDF.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/api/tracker/infrastructure/src/lib/redis/redis-rate-limit.store.ts

@@ -0,0 +1,19 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { REDIS_CLIENT } from '@task-stream/api/shared/infrastructure';
+import { RateLimitStore } from '@task-stream/api/tracker/application';
+import Redis from 'ioredis';
+
+/** A fixed window per key: the first hit opens it, it expires on its own. */
+@Injectable()
+export class RedisRateLimitStore extends RateLimitStore {
+  constructor(@Inject(REDIS_CLIENT) private readonly redis: Redis) {
+    super();
+  }
+
+  async hit(key: string, windowMs: number): Promise<number> {
+    const name = `task-stream:rate:${key}`;
+    const count = await this.redis.incr(name);
+    if (count === 1) await this.redis.pexpire(name, windowMs);
+    return count;
+  }
+}