RFC: Document Export Action Distinctions

[KrisSimon]

Problem

Three EXPORT-role actions exist without clear usage guidance:

Action	Current Usage	Example
<Emit>	Send event	<Emit> a <UserCreated: event> with <user>.
<Store>	Persist to repository	<Store> the <user> into the <user-repository>.
<Publish>	Export variable globally	<Publish> as <alias> <variable>.

Issue

1. All three are classified as EXPORT role in ARO-0009
2. Documentation doesn't explain when to use each
3. Developers may use wrong action for their intent

Examples from Codebase

(* Emit - sends an event for reactive handling *)
<Emit> a <UserCreated: event> with <user>.
(* From: UserService/users.aro:26 *)

(* Store - persists data to a repository *)
<Store> the <user> into the <user-repository>.
(* From: UserService/users.aro:23 *)

(* Publish - rarely used in examples *)
<Publish> as <external-name> <internal-variable>.
(* From: CLAUDE.md examples *)

Proposed Semantic Definitions

Action	Semantic	Persistence	Receiver
<Emit>	Fire-and-forget event	No	Event handlers
<Store>	Persistent data storage	Yes	Repository
<Publish>	Cross-feature-set sharing	Session	Global registry

Decision Matrix

Need	Use
Notify other feature sets of something that happened	<Emit>
Save data for later retrieval	<Store>
Share computed value with other feature sets	<Publish>
Trigger side effects (email, notifications)	<Emit>
Create audit trail	<Store>

Proposed Solution

Add to wiki documentation:

1. Clear semantic definitions for each
2. Decision matrix for choosing
3. Examples showing correct usage

Questions

1. Is <Publish> actually used in practice?
2. Should <Publish> be deprecated in favor of repositories?
3. Are there other EXPORT actions that need clarification?