feat: import Chinese-localized Buzz source snapshot

Signed-off-by: cls_宁波本机 <908705107@qq.com>

examples/countdown-bot/README.md

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+# Countdown Bot
+
+A tiny non-AI Buzz bot example.
+
+The bot is deliberately boring and algorithmic: it listens to one Buzz channel
+and replies to simple commands:
+
+- `!countdown 5` → `5 4 3 2 1 🚀`
+- `!fib 8` → `13 8 5 3 2 1 1 0`
+- `@Countdown Bot fib 8` → `13 8 5 3 2 1 1 0`
+
+It demonstrates that Buzz participants do not have to be LLM agents. Any
+process that can hold a Nostr key, answer NIP-42 auth, publish a kind `0`
+profile, subscribe to events, and publish kind `9` channel messages can be a bot.
+
+On startup it publishes a profile named **Countdown Bot** with a small embedded
+SVG clock icon, then best-effort publishes a NIP-29 `kind:9000` self-add with
+`role=bot`. That channel membership is what makes the bot show up in the
+members list and in Buzz's mention autocomplete.
+
+## Auth paths
+
+### 1. Standalone bot identity
+
+The bot authenticates with its own key only.
+
+Use this when the bot should be admitted as its own independent relay identity.
+
+```bash
+BUZZ_RELAY_URL=ws://localhost:3000 \
+BUZZ_CHANNEL_ID=<channel-uuid> \
+BUZZ_BOT_PRIVATE_KEY=<bot-nsec-or-hex-secret> \
+BUZZ_BOT_AUTH_MODE=standalone \
+cargo run --manifest-path examples/countdown-bot/Cargo.toml
+```
+
+On a closed or allowlisted relay, add the bot pubkey as a relay member or to the
+configured pubkey allowlist before starting it. This path does not reuse an
+owner's access; revoking the bot requires removing this bot pubkey.
+
+### 2. Owner-attested bot identity
+
+The bot still signs messages with its own key, but its NIP-42 `AUTH` event also
+carries a NIP-OA `auth` tag signed by an owner key that is already allowed on the
+relay. This reuses the same owner-attestation credential path that Buzz agents
+receive after the owner/agent OAuth flow: the relay can let the bot connect
+because the owner is a relay member, without making the bot key a persistent
+relay member.
+
+Generate the auth tag on the fly:
+
+```bash
+BUZZ_RELAY_URL=ws://localhost:3000 \
+BUZZ_CHANNEL_ID=<channel-uuid> \
+BUZZ_BOT_PRIVATE_KEY=<bot-nsec-or-hex-secret> \
+BUZZ_OWNER_PRIVATE_KEY=<owner-or-agent-nsec-or-hex-secret> \
+BUZZ_BOT_AUTH_MODE=owner-attested \
+cargo run --manifest-path examples/countdown-bot/Cargo.toml
+```
+
+Or precompute and pass the tag explicitly:
+
+```bash
+BUZZ_AUTH_TAG='["auth","<owner-pubkey>","","<sig>"]' \
+BUZZ_BOT_AUTH_MODE=owner-attested \
+# plus BUZZ_RELAY_URL, BUZZ_CHANNEL_ID, BUZZ_BOT_PRIVATE_KEY
+cargo run --manifest-path examples/countdown-bot/Cargo.toml
+```
+
+Relay requirements for this path:
+
+- `BUZZ_REQUIRE_RELAY_MEMBERSHIP=true` on closed relays.
+- `BUZZ_ALLOW_NIP_OA_AUTH=true` so owner-attested non-member bot keys can be
+  admitted.
+- The owner pubkey must be an active relay member.
+
+Relay access and channel access are separate. Owner-attested auth can admit the
+bot to the relay, but the bot still publishes as its own pubkey. The bot tries to
+self-add to open channels as a `bot` member on startup. For private channels,
+an owner/admin must add the bot pubkey to the channel membership before expecting
+it to appear in members, resolve in mention autocomplete, or read/write messages.
+
+## Try it locally
+
+1. Start Buzz:
+
+   ```bash
+   . ./bin/activate-hermit
+   just setup
+   just relay
+   ```
+
+2. Create or choose a channel in the desktop app and copy its UUID.
+
+3. Run the bot with one of the auth paths above.
+
+4. In the channel, send:
+
+   ```text
+   !countdown 5
+   !fib 8
+   @Countdown Bot fib 8
+   ```
+
+## Notes
+
+- Commands are bounded (`!countdown` and `!fib` max 100) so one message cannot
+  make the bot spam the relay. Out-of-range commands get an explicit help reply.
+- `!fib` replies in descending order because this example is a countdown bot.
+- Mention commands require both text like `@Countdown Bot fib 8` and a `p` tag
+  for the bot pubkey. The Buzz UI adds that tag when the bot is selected from
+  mention autocomplete.
+- The bot ignores its own messages to avoid feedback loops.
+- The example uses direct WebSocket + NIP-42 instead of MCP so the protocol path
+  is easy to inspect in one small file.