feat(sticker): add sticker pack module

Nine commands mirroring the names @Stickers uses: /newpack, /mypack,
/addsticker, /delsticker, /editsticker, /ordersticker, /setpackicon,
/renamepack and /delpack, plus a confirm callback for the destructive
one. Sources are replied stickers, photos or image documents; photos are
downloaded, resampled to 512px and re-uploaded.

One pack per user, keyed by owner id. Creating a pack is the only
operation here that makes a durable, publicly linkable object on a user's
behalf, so it is built around proving ownership rather than assuming it:

- A name is claimed globally and create-only before Telegram is called.
  A pending record alone proves only that a caller *asked* for a name,
  which is exactly what someone naming a victim's public slug also does.
- Adopting an existing set additionally requires that the claim predates
  this invocation. The claim lives in our store and the pack lives at
  Telegram, so a wiped store would otherwise make every pack adoptable.
- Names are released only on positive evidence that no pack stands behind
  them, never on a generic failure, so a transient error cannot hand a
  live name to the next caller.
- Ownership refusals are byte-identical across failure modes, so they
  cannot be used to probe which sets exist.

Error classification is positive-only throughout: "the set is gone" and
"nothing was created" are each proven from a specific Telegram response,
never inferred from an error. Post-action commits run on a context
detached from the request so a shutdown mid-handler cannot lose the
record of something Telegram already did.

Enabled explicitly via MODULES rather than by default.

docs/command-parameter-conventions.md

@@ -15,6 +15,7 @@ remain responsible for parsing and validation.
 |---|---|---|
 | Required value | `<name>` | `<ticker>` |
 | Required comma-separated values | `<name,...>` | `<option,...>` |
+| Required remaining text | `<name...>` | `<title...>` |
 | Optional value | `[name]` | `[date]` |
 | Optional remaining text | `[name...]` | `[target...]` |
 | Alternatives in an optional group | `[literal | literal <name>]` | `[users | user <username>]` |
@@ -40,6 +41,7 @@ language or extra punctuation without a user-facing need.
 
 ```text
 /stock_buy <quantity> <ticker>
+/renamepack <title...>
 /lol [date]
 /trongtruonghop [target...]
 /stats [users | user <username> | cmd <command_name>]