An agent's name was checked for shape and never for meaning:
`Ident::parse` is 1-63 chars of [a-z0-9-] and there was no reserved-name
list anywhere in the tree. So an agent could be called `operator`,
`forge` or `todo` -- names the message layer already produces as a
sender -- and a wake from that component became indistinguishable, at the
broker, from a message sent by the agent.
Adds `RESERVED_NAMES` + `is_reserved_name` to `hive-types`, the zero-dep
leaf both `hive-c0re` and `swarm-controller` already depend on, so
neither grows a dependency to use it.
Every entry is a value some component actually produces as a message
`from`/`to`, taken from `hive-sh4re`'s own sentinel constants rather than
guessed: operator, system, reminder, forge, scheduled, todo, compact,
graceful-stop. Two sentinels are deliberately absent -- `<parent>` and
`<children>` are unreachable as agent names because the charset rejects
them, and `ruth` is a real agent, so wanting that name is a name being
*taken*, which the roster answers.
Deliberately not enforced inside `Ident::parse`: parsing runs on every
read of an already-created name, so rejecting there would make existing
agents unreadable rather than un-creatable -- and it would be a refusal,
which is a stronger action than the warning this is used for today.
`create_agent` now warns on both halves -- a reserved name, and a name
that is also a hive in the roster -- and does not refuse. The warnings
ride on `CreateAgentResponse` rather than only the daemon's log, because
the person who can still fix the name in one keystroke is holding the
response, not reading the journal. `skip_serializing_if` keeps the
no-warning JSON byte-identical to before, so this is a non-breaking first
step toward refusing later.
`hive-sh4re` gains a drift test tying its sentinel constants to the list:
two crates that cannot import each other's intent now fail loudly if a
sentinel is added without being reserved. Mutation-verified -- forcing
the predicate false, forcing it true, and dropping a single entry each
turn a different test red.
Second increment of the per-crate README effort, covering the rest of the
infra/wire/priv column: hive-priv, hive-metric, hive-types, hive-sh4re,
hive-core-agent-sock, hive-agent-sock. Same shape as the first batch —
purpose + when-to-use, and point at the crate-root //! docs plus the
relevant docs/ pages rather than duplicating them. Wires
readme = "README.md" into each Cargo.toml [package].
Disjoint from the batch-1 crates, so the two increments compose cleanly.
