add package: pyproject + src (DPYWebhooks, store protocol, cap + self-heal, fail-loud)

Signed-off-by: disqualifier <dev@disqualifier.me>

README.md

@@ -27,6 +27,21 @@ With a persistence store so webhooks survive a restart:
 hooks = DPYWebhooks(bot, store=my_store)
 ```
 
+Work with **all** of a channel's existing webhooks (read live, no store, no create) — for
+discovery, load-spreading, or rotation:
+
+```python
+await hooks.list(channel)                              # every live webhook on the channel
+await hooks.pick(channel, strategy="round_robin")      # select one existing (None if none)
+await hooks.send_any(channel, strategy="round_robin", content="hi")  # send via a picked one
+```
+
+`pick` strategies are `"first"` (oldest by id), `"random"`, and `"round_robin"` (per-channel
+in-process index that wraps on the live count and rebuilds if the count changed); an unknown
+strategy raises `ValueError`. `send_any` sends through a picked existing webhook, **falling
+back to `get_or_create`** when the channel has none, and reuses the same dead-webhook
+self-heal. None of these three create or touch the store — they read live from the channel.
+
 ## What you inject
 
 - **`client`** — your `discord.Client` / `commands.Bot`. Used to rebuild persisted webhooks
@@ -57,6 +72,10 @@ The module docstring (`help(dpy_webhooks)` / IDE hover) is the source of truth.
   self-heal
 - `clear(channel) -> None` — delete server-side + store record (idempotent)
 - `count(channel) -> int` — webhooks currently on the channel
+- `list(channel) -> list[discord.Webhook]` — all live webhooks on the channel (no create)
+- `pick(channel, *, strategy="first") -> discord.Webhook | None` — select an existing one
+- `send_any(channel, *, strategy="round_robin", **kwargs) -> discord.WebhookMessage` — send
+  via a picked existing webhook, falling back to `get_or_create`
 
 **Self-heal.** If `send` hits a dead webhook (deleted server-side / invalid token), the lib
 clears the record, recreates the webhook, and retries the send **once**; a second failure