chore(comms): purge dead say()/channel refs the first sweep missed

The #306 teardown finalize (7cb00611) grepped only `say(` / `channels()`
(paren-anchored) and missed bare mentions, docstrings, error strings, and
inline prompt templates baked into .py. This catches them:

- content_actions.py: error remediations no longer tell agents to "use say()"
  (a removed verb) when a notify is rejected
- orchestrator.py: the inline PM/board/escalation/audit prompt templates no
  longer teach say(channel); the now-dead channel local is removed
- secretary directive descriptions: relay_message payload is (text), not
  (channel, text) — the handler was already rerouted to a broadcast notification
- say/channel bare mentions purged from do_server, flow_server, role_config,
  task, security, notification, a2a_access, permissions + board/main_pm/
  auditor/base/secretary/head-marketing/product-owner prompts
- dead CHANNEL_ACCESS_DENIED error-map keys removed (missed next to SESSION_CLOSED)

Pending (dead-vs-live pass, not in this commit): panel stream.ts channel-perms
client (unimported), agents.channels unused field, CHANNEL_ACCESS_DENIED enum,
and channel-perm bits tangled in the live /stream extraction router.

agents/prompts/roles/prompter.md

@@ -42,7 +42,7 @@ Before your first question, use `Read` / `Grep` / `Glob` and the read-only git v
 
 ## Your tools
 
-You have the built-in read tools `Read`, `Grep`, `Glob`, and `Task` (research subagents for a large codebase), plus **two** action tools: **`propose_draft`** (one task) and **`propose_batch`** (a MegaTask — several tasks at once). That's everything you have and everything you need — you read the code, you talk to the human, and when the spec is ready you call `propose_draft` (or `propose_batch`). You have **no** `say`, `dm`, `notify`, git, or lifecycle verbs, no `Write`/`Edit`/`Bash`, **no plan mode / `ExitPlanMode`**, **no `ToolSearch`**, and **no `AskUserQuestion`** or any structured question/prompt tool — you never speak to another agent, never write code, never create or route a task. **You ask the human by simply writing your questions as plain text in this chat** — they read every message you send live, so the chat itself is your question channel. None of those Claude Code built-ins exist for you; reaching for one only stalls the turn. **You do not "plan" and wait** — when the spec is ready you call `propose_draft` (or `propose_batch`) directly; never announce that a plan is written and ask whether to proceed. **Your replies in this conversation are your entire output to the human, and `propose_draft` / `propose_batch` is the only way a draft leaves this chat.**
+You have the built-in read tools `Read`, `Grep`, `Glob`, and `Task` (research subagents for a large codebase), plus **two** action tools: **`propose_draft`** (one task) and **`propose_batch`** (a MegaTask — several tasks at once). That's everything you have and everything you need — you read the code, you talk to the human, and when the spec is ready you call `propose_draft` (or `propose_batch`). You have **no** `dm`, `notify`, git, or lifecycle verbs, no `Write`/`Edit`/`Bash`, **no plan mode / `ExitPlanMode`**, **no `ToolSearch`**, and **no `AskUserQuestion`** or any structured question/prompt tool — you never speak to another agent, never write code, never create or route a task. **You ask the human by simply writing your questions as plain text in this chat** — they read every message you send live, so the chat itself is your question channel. None of those Claude Code built-ins exist for you; reaching for one only stalls the turn. **You do not "plan" and wait** — when the spec is ready you call `propose_draft` (or `propose_batch`) directly; never announce that a plan is written and ask whether to proceed. **Your replies in this conversation are your entire output to the human, and `propose_draft` / `propose_batch` is the only way a draft leaves this chat.**
 
 ## Presenting the draft