feat(cli+docs+smoke): inference-task CLI + GC ticker + smoke + docs (v5 Stage 4)

CLI surface for the durable queue:

- `mcpctl get tasks` — table view (ID, STATUS, POOL, LLM, MODEL,
  STREAM, AGE, WORKER). Aliases `task`, `tasks`, `inference-task`,
  `inference-tasks` all normalize to the canonical plural so URL
  construction works uniformly. RESOURCE_ALIASES + completions
  generator updated.
- `mcpctl chat-llm <name> --async -m <msg>` — enqueue and exit. stdout
  is just the task id (pipeable into `xargs mcpctl get task`); stderr
  carries human-readable status. REPL mode is rejected for --async
  (fire-and-forget doesn't make sense without -m).

GC ticker in mcpd: 5-min interval. Pending tasks past 1 h queue
timeout flip to error with a clear message; terminal tasks past 7 d
retention get deleted. Both queries are index-backed.

Crash fix uncovered by the smoke: when the async route doesn't await
ref.done, a later cancel/error rejected the in-flight Promise as
unhandled and crashed mcpd. The route now attaches a no-op `.catch`
so the legacy `done` semantic still works for sync callers (chat,
direct infer) without taking out the process for async ones. The
EnqueueInferOptions also gained an explicit `ownerId` field so the
async API can stamp the authenticated user on the row instead of
inheriting 'system' from the constructor's resolveOwner — without
this, every GET/DELETE from the original caller would 404 due to
foreign-owner mismatch.

Smoke (tests/smoke/inference-task.smoke.test.ts):

  1. POST /inference-tasks while no worker bound → row=pending.
  2. Bring a registrar online → bindSession drain claims and
     dispatches → worker complete()s → row=completed → GET returns
     the assistant body.
  3. Stop worker, enqueue, DELETE → row=cancelled, persisted.

docs/inference-tasks.md (new): full data model, lifecycle diagram,
async API reference, CLI examples, RBAC table, GC defaults, and the
v5 limitations / v6 roadmap. Cross-linked from virtual-llms.md and
agents.md.

Tests + smoke: mcpd 893/893, mcplocal 723/723, cli 437/437, full
smoke 146/146 (was 144, +2 new task smoke). Live mcpd verified via
manual curl: enqueue → cancel → re-fetch — no crash, owner scoping
returns 404 on foreign ids, GC ticker logs at info when it sweeps.

v5 complete: durable queue (Stage 1) + VirtualLlmService rewire
(Stage 2) + async API & RBAC (Stage 3) + CLI/GC/smoke/docs (Stage 4).

completions/mcpctl.fish

@@ -31,10 +31,10 @@ function __mcpctl_has_project
 end
 
 # Resource type detection
-set -l resources servers instances secrets secretbackends llms agents personalities templates projects users groups rbac prompts promptrequests serverattachments proxymodels all
+set -l resources servers instances secrets secretbackends llms agents personalities templates projects users groups rbac prompts promptrequests serverattachments proxymodels inference-tasks all
 
 function __mcpctl_needs_resource_type
-    set -l resource_aliases servers instances secrets secretbackends llms agents personalities templates projects users groups rbac prompts promptrequests serverattachments proxymodels all server srv instance inst secret sec secretbackend sb llm agent personality template tpl project proj user group rbac-definition rbac-binding prompt promptrequest pr serverattachment sa proxymodel pm
+    set -l resource_aliases servers instances secrets secretbackends llms agents personalities templates projects users groups rbac prompts promptrequests serverattachments proxymodels inference-tasks all server srv instance inst secret sec secretbackend sb llm agent personality template tpl project proj user group rbac-definition rbac-binding prompt promptrequest pr serverattachment sa proxymodel pm task tasks inference-task
     set -l tokens (commandline -opc)
     set -l found_cmd false
     for tok in $tokens
@@ -72,13 +72,14 @@ function __mcpctl_resolve_resource
         case promptrequest promptrequests pr; echo promptrequests
         case serverattachment serverattachments sa; echo serverattachments
         case proxymodel proxymodels pm; echo proxymodels
+        case task tasks inference-task inference-tasks; echo inference-tasks
         case all;                     echo all
         case '*';                      echo $argv[1]
     end
 end
 
 function __mcpctl_get_resource_type
-    set -l resource_aliases servers instances secrets secretbackends llms agents personalities templates projects users groups rbac prompts promptrequests serverattachments proxymodels all server srv instance inst secret sec secretbackend sb llm agent personality template tpl project proj user group rbac-definition rbac-binding prompt promptrequest pr serverattachment sa proxymodel pm
+    set -l resource_aliases servers instances secrets secretbackends llms agents personalities templates projects users groups rbac prompts promptrequests serverattachments proxymodels inference-tasks all server srv instance inst secret sec secretbackend sb llm agent personality template tpl project proj user group rbac-definition rbac-binding prompt promptrequest pr serverattachment sa proxymodel pm task tasks inference-task
     set -l tokens (commandline -opc)
     set -l found_cmd false
     for tok in $tokens
@@ -526,6 +527,7 @@ complete -c mcpctl -n "__fish_seen_subcommand_from chat-llm" -l system -d 'Optio
 complete -c mcpctl -n "__fish_seen_subcommand_from chat-llm" -l temperature -d 'Sampling temperature (0..2)' -x
 complete -c mcpctl -n "__fish_seen_subcommand_from chat-llm" -l max-tokens -d 'Maximum tokens in the assistant reply' -x
 complete -c mcpctl -n "__fish_seen_subcommand_from chat-llm" -l no-stream -d 'Disable SSE streaming (single JSON response)'
+complete -c mcpctl -n "__fish_seen_subcommand_from chat-llm" -l async -d 'Enqueue as a durable inference task and print the task id (does not wait for completion). Virtual Llms only. Poll with `mcpctl get task <id>`.'
 
 # console options
 complete -c mcpctl -n "__fish_seen_subcommand_from console" -l stdin-mcp -d 'Run inspector as MCP server over stdin/stdout (for Claude)'