feat(vision): gate recognition on a configured provider

Expose ImageRecognitionRuntime.available() and gate the image-task pre-step
injection on it, so the capability is dormant until an endpoint is
configured instead of guiding the model to a call that can only fail.

Co-Authored-By: Claude <noreply@anthropic.com>

packages/vision/tool-image-recognition/README.md

@@ -96,5 +96,9 @@ Prefix-stable while the guidance text is unchanged.
 
 ## Known Limitations and Deferred Work
 
+- **Dormant until configured:** the image-task injection is gated on a usable
+  provider, so without a configured endpoint the capability is inert and the
+  model is not guided to recognition. Direct `recognize_image` calls then throw
+  a clear `ImageRecognitionError`.
 - Path/URL detection is heuristic and can be disabled; misdetections are possible.
 - Requires a configured, available provider — see `dsh-image-recognition-http`.

packages/vision/tool-image-recognition/src/index.ts

@@ -150,6 +150,9 @@ export function apply(ctx: Context, config: Config = {}): void {
     const decision = await next()
     if (decision.kind === 'reject') return decision
     if (!hasImageSignal(decision.messages, detectBlocks, detectPaths)) return decision
+    // Dormant until configured: without a usable provider the recognition
+    // surface is inert, so the model is not guided to a call that can only fail.
+    if (!ctx.imageRecognition.available()) return decision
     signal.throwIfAborted()
     const lookup = { cwd: agent.session.header.cwd, signal, scope: agent }
     const skill = await ctx.skills.get(SKILL_NAME, lookup)