feat(cron-recipes): /cron-recipe <name> seeds a conversational fill

Reworks the chat-line UX: pick a recipe by name and the agent asks you for
what it needs, one question at a time, instead of forcing you to hand-type a
slot=val command line.

- /cron-recipe                  -> lists the catalog
- /cron-recipe <name>           -> forgiving name match (exact/prefix/substring/
                                   fuzzy; ambiguous lists candidates), then seeds
                                   the agent with a natural-language fill request
                                   built from the recipe's typed slots + schedule
                                   and prompt templates. The agent asks for each
                                   value one at a time and calls the EXISTING
                                   cronjob tool. No new tool.
- /cron-recipe <name> slot=val  -> unchanged deterministic path (fill_recipe ->
                                   create_job) for the dashboard/docs/power user.

Mechanism (no new plumbing, invariant-safe — the seed enters as a normal user
turn, never a synthetic injection):
- shared handler returns RecipeCommandResult{text, agent_seed}; match_recipe()
  and build_recipe_seed() are the new shared pieces.
- gateway: dispatch rewrites event.text to the seed and falls through to the
  agent (the same pattern /steer uses).
- CLI: handler sets a one-shot self._pending_agent_seed; the interactive loop
  consumes it right after process_command() and runs it as the next turn.

The typed-slot schema stays the single source of truth (still validates the
form/inline path via fill_recipe); the agent path just renders those slots into
the questions to ask. Docs updated to lead with the name-then-ask flow.

website/docs/reference/cron-recipes-catalog.mdx

@@ -15,9 +15,11 @@ Every recipe works from **every surface**:
 
 - **Dashboard / desktop app** — open the Cron page, switch to the **Recipes**
   tab, fill the form, and click *Schedule it*.
-- **CLI, TUI, and messengers** — copy a recipe's `/cron-recipe` command below,
-  edit the values, and send it. Hermes fills in anything you leave out and
-  asks if something's ambiguous.
+- **CLI, TUI, and messengers** — type `/cron-recipe <name>` (e.g.
+  `/cron-recipe morning-brief`) and Hermes asks you for what it needs, one
+  question at a time, then schedules it. The name match is forgiving — a
+  prefix or near-spelling resolves. Power users can skip the questions by
+  passing values inline: `/cron-recipe morning-brief time=08:00`.
 - **Desktop app** — click **Send to App** on any recipe and it opens with the
   command pre-loaded in your composer.