fix(prompts): compose the prompter role layer for the intake agent (#116)

The intake (prompter) agent was spawned with its role prompt missing, so it
only saw the gateway verbs layer (whose sole verb is `i_am_idle`) plus the
base rules. It concluded it had no way to act and refused to draft tasks —
the live intake chat produced empty turns and never called `propose_draft`.

Root cause: `prompter` was absent from `_ROLE_LAYER_MAP`, so `compose_prompt`
silently skipped `agents/prompts/roles/prompter.md` — the interviewer prompt
that defines the intake mission and the `propose_draft` tool. The tool was
wired into the SDK the whole time; the agent was just never told it existed.

Fix: map `prompter` to `prompter.md` so the role layer is composed in, the
same as every other role.

roboco/agents/factories/_base.py

@@ -61,6 +61,10 @@ _ROLE_LAYER_MAP: dict[str, str] = {
     "product_owner": "board.md",
     "head_marketing": "board.md",
     "auditor": "board.md",
+    # Intake interviewer — the live-session role prompt that wires up the
+    # propose_draft mission. Without this the prompter only sees the
+    # gateway verbs layer (i_am_idle) and refuses to draft.
+    "prompter": "prompter.md",
 }
 
 _TEAM_LAYER_MAP: dict[str, str] = {