feat(FN-2481): align Hermes runtime artifacts and compatibility coverage

- Regenerate fusion-plugin-hermes-runtime build artifacts and manifest metadata for runtime packaging
- Refactor Hermes runtime source into dedicated pi-module, runtime-adapter, and shared type modules
- Expand Hermes and engine plugin-runner tests to validate cross-runtime compatibility behavior
- Update getting-started, settings reference, and Hermes README docs to reflect the current runtime integration guidance

plugins/fusion-plugin-hermes-runtime/README.md

@@ -1,34 +1,16 @@
 # Hermes Runtime Plugin
 
-> **Status:** Experimental placeholder runtime (current behavior)
+Provides an executable Hermes runtime plugin for Fusion. This package enables runtime registration, discovery, and session execution so agents configured with `runtimeConfig.runtimeHint: "hermes"` can run through the standard runtime adapter contract.
 
-Provides a Hermes runtime plugin for Fusion. The plugin is active today for runtime registration/discovery and runtime selection via `runtimeConfig.runtimeHint: "hermes"`.
+## Overview
 
-## What it does today
+This plugin follows the runtime adapter pattern used by other executable plugin runtimes:
 
-- Registers Hermes runtime metadata with the plugin system
-- Exposes a runtime factory that returns a placeholder runtime object
-- Emits `hermes-runtime:loaded` on plugin load
-- Supports runtime routing with `runtimeHint: "hermes"`
-
-## Current behavior and limitations
-
-This plugin currently provides **registration + placeholder execution semantics**.
-
-- Runtime factory returns an object with:
-  - `runtimeId: "hermes"`
-  - `version: "0.1.0"`
-  - `status: "deferred"`
-  - `message` describing placeholder/deferred status
-  - `execute()` function
-- Calling `execute()` always throws a not-implemented error.
-- Runtime creation itself does **not** throw.
-
-Expected execution failure message includes:
-
-```
-Hermes runtime is not yet implemented. Full implementation deferred to FN-2264. See https://github.com/gsxdsm/fusion/issues/FN-2264
-```
+- Registers Hermes runtime metadata for resolver discovery
+- Creates executable runtime sessions via `createFnAgent`
+- Delegates prompt execution through `promptWithFallback`
+- Exposes model descriptions through `describeModel`
+- Supports best-effort session disposal via `dispose()`
 
 ## Installation
 
@@ -44,9 +26,18 @@ cp -r fusion-plugin-hermes-runtime ~/.fusion/plugins/
 fn plugin add ./plugins/fusion-plugin-hermes-runtime
 ```
 
-## Runtime routing (`runtimeHint`)
+## Runtime Metadata
 
-To route an agent to Hermes, set `runtimeConfig.runtimeHint` to `"hermes"`:
+- **Plugin ID:** `fusion-plugin-hermes-runtime`
+- **Package name:** `@fusion-plugin-examples/hermes-runtime`
+- **Runtime ID:** `hermes`
+- **Runtime name:** `Hermes Runtime`
+- **Version:** `0.1.0`
+- **Description:** Hermes-backed AI session using the user's configured pi provider and model
+
+## Agent Configuration
+
+Configure an agent to target Hermes via `runtimeConfig.runtimeHint`:
 
 ```json
 {
@@ -58,66 +49,12 @@ To route an agent to Hermes, set `runtimeConfig.runtimeHint` to `"hermes"`:
 }
 ```
 
-> ⚠️ With the current placeholder runtime, agent/session selection can target Hermes successfully, but runtime `execute()` will throw.
-
-## Source-of-truth metadata
-
-### `manifest.json`
-
-```json
-{
-  "id": "fusion-plugin-hermes-runtime",
-  "name": "Hermes Runtime Plugin",
-  "version": "0.1.0",
-  "description": "Hermes AI runtime plugin for Fusion - provides AI agent execution runtime capabilities",
-  "author": "Fusion Team",
-  "homepage": "https://github.com/gsxdsm/fusion",
-  "runtime": {
-    "runtimeId": "hermes",
-    "name": "Hermes Runtime",
-    "description": "Experimental Hermes runtime integration for Fusion tasks (implementation deferred to FN-2264)",
-    "version": "0.1.0"
-  }
-}
-```
-
-### Runtime metadata (from `src/index.ts`)
-
-- **Runtime ID:** `hermes`
-- **Name:** `Hermes Runtime`
-- **Version:** `0.1.0`
-- **Description:** `Experimental Hermes runtime integration for Fusion tasks (implementation deferred to FN-2264)`
-
-## Development
+## Local Development
 
 ```bash
-# Install dependencies
-pnpm install
-
 # Run plugin tests
 pnpm --filter @fusion-plugin-examples/hermes-runtime test
 
-# Build
-pnpm build
+# Build plugin output to dist/
+pnpm --filter @fusion-plugin-examples/hermes-runtime build
 ```
-
-## Test coverage
-
-The plugin tests validate:
-
-- Manifest identity
-- Runtime registration + metadata consistency
-- Placeholder runtime return shape (`status: "deferred"`)
-- `execute()` failure semantics
-- Hook behavior (`onLoad`, `onUnload`, event emission)
-
-## Exports
-
-- `default` — plugin instance
-- `hermesRuntimeMetadata` — runtime metadata object
-- `hermesRuntimeFactory` — runtime factory
-- `HERMES_RUNTIME_ID` — runtime ID constant (`"hermes"`)
-
-## License
-
-MIT