Wire hark dialect publish/subscribe/query/list through the daemon (closes #4) #5

First slice of issue #4 — the fire-and-forget meta verbs that don't
need router-reply correlation.
CLI: re-adds `hark dialect <subcommand>` with `subscribe <pattern>`
and `unsubscribe` variants. Pattern defaults to `*`. Handlers call
new `LocalApiClient` methods instead of just printing a frame.
Daemon: new endpoints
 POST /v1/agents/<handle>/meta/subscribe { "pattern": "..." }
 POST /v1/agents/<handle>/meta/unsubscribe
Both build the canonical `(meta (subscribe (speak? <p>)))` or
`(meta (unsubscribe))` frame and submit via the existing
`send_outbound` path. Subscribe pattern is validated locally
(non-empty, no whitespace/parens/quotes) — new
`invalid_subscribe_pattern` error code → exit 2.
Router builders: adds `build_meta_unsubscribe_frame` and
`build_meta_query_list_frame` alongside the existing teach/query/
subscribe helpers, plus unit tests.
Wire compatibility: bumps LOCAL_API_VERSION 2 → 3. New endpoints are
the schema change.
End-to-end verified against a live cbcl-router: subscribe → producer
teach to a matching name → push lands in `hark recv`; unsubscribe →
subsequent matching teach does NOT arrive (recv_timeout).
cargo test: 122 passed (9 suites).
publish, query, list — the verbs that need router-reply correlation
and dialect-cache integration — are deferred to follow-up commits on
this branch.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Second slice of issue #4. Sends `(meta (teach @router <define>))` to
the router, awaits the reply, parses `digest` + `name`, returns them
to the CLI.
Correlation primitive (the load-bearing new piece):
- `AgentEntry.pending_meta_reply: Option<oneshot::Sender<String>>`
 single-slot per agent.
- `AgentStore::send_meta_and_await(handle, frame, timeout)`
 atomically claims the slot, sends via `send_outbound`, awaits the
 oneshot. Concurrent callers see `MetaSendBusy`. Timeouts clear the
 slot so the next attempt can proceed.
- `AgentStore::try_route_meta_reply(handle, message)` — called from
 the receive loop before `enqueue_inbound`; routes the frame to the
 pending sender if filled, otherwise returns the message so the
 caller falls through to the normal recv queue.
- Receive loop: classifies inbound frames; `DialectPush` and a new
 `MetaReply` class try the pending slot first. Unmatched DialectPush
 still installs into the cache + enqueues as before; unmatched
 MetaReply passes through to recv unchanged.
Classifier:
- New `InboundClass::MetaReply` for bare `(reply ...)` frames at the
 top level. Normal asks come wrapped in `(lang <dialect> (ask ...))`
 and stay as `Ordinary`.
Validation:
- The daemon runs `cbcl_parser::run_pipeline` on `(meta <define>)`
 before sending — mirroring the dialect cache's install-time guard
 on the receive path. An R1–R5 violation surfaces as
 `cbcl_validation_failed` (exit 8) without ever leaving the daemon.
Endpoint:
 POST /v1/agents/<handle>/meta/publish
 body: { "define": "(define <name> ...)" }
 200: { "ok": true, "digest": "...", "name": "..." }
CLI:
 hark dialect publish [--define '(define ...)'] [--json]
 Reads the define from --define or stdin; prints `<digest> <name>`
 on success, or JSON if --json is given.
New error codes wired in CLI mapping:
- `meta_send_busy` → exit 7 (agent handle unavailable)
- `meta_reply_timeout` → exit 10 (timeout)
- `meta_reply_malformed` / `meta_reply_missing_{digest,name}` → exit 12 (internal)
End-to-end verified against a live cbcl-router:
- Valid define: `<digest> name` printed, idempotent under
 content addressing (re-publish returns identical digest).
- R3 violation: caught locally, never reaches the router; CLI
 exits 8 with the cbcl-rs diagnostic.
cargo test: 122 passed (9 suites).
Query + list still deferred — they need cache-install integration
for the teach-back response and a list-reply parser. Same correlation
primitive carries them; coming in the next commit.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Third slice of issue #4. Both reuse the meta-reply correlation primitive
(`send_meta_and_await` + `try_route_meta_reply`) shipped with the
publish slice.
query <name>:
- Daemon sends `(meta (query (speak? <name>)))` and awaits the reply.
- Two reply shapes possible — teach-back `(meta (teach @<self> (define
 <name> ...)))` on hit, or `(reply ...)` with `:reason "router-does-not-
 speak"` on miss. The handler discriminates by leading `(meta` vs
 anything else.
- On hit: classify_inbound's existing DialectPush path extracts name +
 define_form; daemon computes the SHA-256 digest and returns
 {digest, name, define}. The receive loop installs into the local
 cache as a side effect (same code path as subscriber pushes — the
 pieces line up because R3 forces dialect-perf names disjoint from
 cores and the teach-back shape is structurally identical).
- On miss: 404 with `dialect_unknown_to_router` carrying the router's
 reason. CLI exit 2 (usage).
list:
- Daemon sends `(meta (query (list)))` and awaits the reply.
- Parses `:names "a b c"` from `(reply ...)` via the same param parser
 as publish. Returns names as a Vec.
- CLI prints one per line.
Receive loop change:
- Cache install for DialectPush now runs BEFORE the meta-reply routing
 check, so query teach-backs and subscriber pushes BOTH install. If
 the frame is then routed to a pending meta-await, we still emit
 `InboundOutcome::Installed(name)` so the auto re-hello path fires
 whenever a new dialect lands in the cache regardless of which path
 produced it.
CLI:
 hark dialect query <name> [--json]
 Prints `<digest> <name>` (or JSON with `define`) on hit.
 hark dialect list
 Prints each known dialect name on its own line.
Endpoints:
 POST /v1/agents/<handle>/meta/query { "name": "..." }
 → 200 { digest, name, define }
 → 404 { error.code: "dialect_unknown_to_router" }
 POST /v1/agents/<handle>/meta/list
 → 200 { names: ["a", "b", ...] }
End-to-end verified against a live cbcl-router:
- list returns every published name
- query <known> returns the digest + name + define (and installs the
 define into the local cache as a side effect)
- query <unknown> exits 2 with `dialect_unknown_to_router`
- query --json emits structured output
cargo test: 122 passed (9 suites). Closes issue #4.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Updates README, specs/cli.md, and specs/local-api.md for the five new
dialect verbs that close issue #4.
README:
- New Workflow snippet showing list / query / publish / subscribe /
 unsubscribe with one-line examples and the R1–R5 + 404 semantics
 callouts.
- New `### dialect <verb>` sections under Commands.
- Adds the new local-API error codes to the existing list:
 invalid_subscribe_pattern, meta_send_busy, meta_reply_timeout,
 dialect_unknown_to_router, meta_reply_malformed,
 meta_reply_missing_{digest,name}.
specs/local-api.md:
- Documents POST /v1/agents/<handle>/meta/{subscribe,unsubscribe,
 publish,query,list} with request/response shapes, error codes, and
 the meta-reply correlation contract (single-slot per agent,
 10-second default timeout, meta_send_busy on concurrent calls).
- Extends the stable error-code list with the new codes.
specs/cli.md:
- New `### dialect <verb>` sections with stdout shape, exit codes, and
 the JSON-output variants where applicable.
- Notes content-addressed idempotence for publish and the local cache
 install side effect for query.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

- Reject non-define publish bodies before they reach the router; the
 parsed form's head must be `define`, not any valid meta op.
- Correlate meta replies with the in-flight request via a new
 MetaReplyExpectation slot, so an unsolicited subscription push can't
 satisfy a pending publish/list/query waiter.
- Surface teach-back install failures as teach_back_rejected on query
 instead of reporting a digest for a define that wasn't installed.
- Drop pending meta waiters when the handle goes unhealthy so callers
 fail fast on a closed connection instead of waiting META_REPLY_TIMEOUT.
- Enforce the documented subscribe wildcard grammar locally (`*`,
 trailing prefix*, or exact name); reject foo*bar, **, and *foo.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Move the pending-meta-waiter cleanup into `AgentEntry::mark_unhealthy`
so every unhealthy path drops the slot. The previous fix only covered
`AgentStore::mark_unhealthy`, leaving `enqueue_inbound`'s
queue-overflow case (which calls the entry method directly) blocking
the waiter until META_REPLY_TIMEOUT. Reachable now that unrelated
subscription pushes fall through to the inbound queue.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>