Find WhatsApp contacts and groups

Find WhatsApp contacts and groups

The agent gets the tool whatsapp_find, which gives the contacts and
groups of the user whose name holds a text, with no regard to case and
accents, as lines "ID | name | contact or group", at most 20 and the
number of the others. The send tool of the next step takes these IDs.

The contacts come from the session database of the library, with the
full, first, business, and push names, and with no copy. The groups come
from WhatsApp and stay in memory for one hour; the batches use the same
names. When the groups cannot be read and none are known, the answer
says so. Before the names arrive from the phone, the tool says that they
are not ready, and without a link it tells the agent to ask the user to
run /whatsapp pair PHONE.

Only the root agent has the tool: the toolbox of a subagent has no
WhatsApp, so it is an unknown tool there. The new tool changes the tool
list, so the prompt cache misses once. The match uses golang.org/x/text,
which the library needs already, so the vendor hash changes only for its
packages.

Issue: 6f69ca1