chore(openspec): archive cloud-planner-proxy

Change is complete (20/20 tasks). Deltas synced: MODIFIED the
agent-runtime "Pluggable dual-provider tool-calling abstraction"
requirement (added transport selection), and created a new main spec
openspec/specs/cloud-planner-proxy/spec.md.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

openspec/specs/agent-runtime/spec.md

@@ -42,9 +42,16 @@ tool.
 
 ### Requirement: Pluggable dual-provider tool-calling abstraction
 The system SHALL support at least two interchangeable LLM providers
-(Anthropic native tool use and OpenAI function calling) for the AI Planner's
-decision calls, selectable via configuration, with both providers
-constrained to return exactly one tool call per request.
+(Anthropic native tool use and OpenAI function calling) for the AI
+Planner's decision calls, selectable via configuration, with both providers
+constrained to return exactly one tool call per request. Independently of
+provider selection, the system SHALL support at least two transports for
+making that decision call -- direct-to-provider (the tool-calling client
+calls the provider's SDK itself, using locally configured credentials) and
+cloud-proxy (the tool-calling client calls the Cloud Control Plane's
+planner-decision endpoint, which calls the provider using cloud-held
+credentials) -- selectable via configuration without requiring any change
+to `AIPlanner`'s own decision logic.
 
 #### Scenario: Provider selected via configuration
 - **WHEN** the AI Planner is configured with a given provider identifier
@@ -57,6 +64,29 @@ constrained to return exactly one tool call per request.
 - **THEN** the response is parsed into exactly one tool name and one
   arguments object, regardless of which provider produced it
 
+#### Scenario: Transport selected via configuration
+- **WHEN** the Host Agent is configured with a given transport (direct or
+  cloud-proxy)
+- **THEN** `AIPlanner` is constructed with the tool-calling client for that
+  transport, and its own decision logic is unchanged regardless of which
+  transport is in effect
+
+#### Scenario: Cloud-proxy transport is the default
+- **WHEN** no transport is explicitly configured
+- **THEN** the AI Planner uses the cloud-proxy transport and the Cloud
+  Control Plane's planner-decision endpoint
+
+#### Scenario: Direct transport remains available by explicit configuration
+- **WHEN** the Host Agent is configured with the direct transport
+- **THEN** the AI Planner uses the direct-to-provider transport with locally
+  configured credentials
+
+#### Scenario: Cloud-proxy transport resolves a decision without a local provider client
+- **WHEN** the Host Agent is configured with the cloud-proxy transport
+- **THEN** its tool-calling client sends the decision request to the Cloud
+  Control Plane's planner-decision endpoint instead of constructing a local
+  Anthropic or OpenAI SDK client
+
 ### Requirement: AI Planner is disabled by default and additive to the existing Planner
 The system SHALL default to the existing non-LLM Planner unless the AI
 Planner is explicitly enabled via configuration, and SHALL NOT alter the