feat(mcpd+cli+mcplocal): /llms/<name>/members + POOL column + --pool-name (v4 Stage 2)

Surfaces the v4 pool model end-to-end:

- mcpd: GET /api/v1/llms/:name/members returns the effective pool the
  named anchor belongs to, plus aggregate stats (size, activeCount,
  explicit vs implicit pool key). RBAC inherits from `view:llms` —
  same as the single-Llm route. Members are full LlmView shapes so
  callers don't need a second roundtrip to render the pool block.

- mcpd: VirtualLlmService.register accepts an optional `poolName` on
  RegisterProviderInput; the route's `coerceProviderInput` validates
  the same character set as CreateLlmSchema.poolName. Backwards
  compatible — older mcplocals that don't send the field continue to
  publish solo Llms.

- CLI `get llm` table: new POOL column right after NAME. Solo rows
  show "-" so the "no pool / pool of 1" case is unambiguous (per
  user direction "make sure we see it, prominently visible and
  impossible to mistake").

- CLI `describe llm`: fetches /members and renders a Pool block at
  the top of the detail view when the row is in an explicit pool OR
  when its implicit pool has size > 1. Each member line shows
  kind/status; the anchor row gets "← this row". Block is suppressed
  for solo rows so describe stays compact in the common case.

- CLI `create llm --pool-name <name>` flag and apply schema both
  accept the new field. Yaml round-trip preserves it: get -o yaml
  emits `poolName: <name>`, apply -f re-imports it without diff.
  Verified end-to-end against the live mcpd.

- mcplocal: LlmProviderFileEntry gains optional `poolName`; main.ts
  and registrar.ts thread it through into the register payload. Use
  case for distributed inference: each user's mcplocal picks a
  unique `name` (e.g. `vllm-<host>-qwen3`) but a shared `poolName`
  (e.g. `user-vllm-qwen3-thinking`); agents see one logical pool
  that auto-grows as workers come online.

- Shell completions: regenerated from source via the existing
  scripts/generate-completions.ts. `--pool-name` now suggests in
  fish + bash for `mcpctl create llm`.

Tests: +3 new mcpd route tests for /members (explicit pool, solo
pool of 1, missing-anchor 404). All suites green:
  mcpd 868/868 (was 865, +3),
  mcplocal 723/723,
  cli 437/437.

Stage 3 (next): live smoke against 2 publishers sharing a pool name +
docs.

completions/mcpctl.bash

@@ -185,7 +185,7 @@ _mcpctl() {
             COMPREPLY=($(compgen -W "--data --force -h --help" -- "$cur"))
             ;;
           llm)
-            COMPREPLY=($(compgen -W "--type --model --url --tier --description --api-key-ref --extra --force --skip-auth-check -h --help" -- "$cur"))
+            COMPREPLY=($(compgen -W "--type --model --url --tier --description --api-key-ref --extra --pool-name --force --skip-auth-check -h --help" -- "$cur"))
             ;;
           agent)
             COMPREPLY=($(compgen -W "--llm --project --description --system-prompt --system-prompt-file --proxy-model --default-temperature --default-top-p --default-top-k --default-max-tokens --default-seed --default-stop --default-extra --default-params-file --force -h --help" -- "$cur"))