fix(connectivity): catalog ModelConfigs inherit the platform maxTokens

[teemow]

Closes #702.

Problem

A kagent.modelConfigs[] entry of the connectivity chart renders no maxTokens, so an agent on a catalog model (anthropic-opus-5, anthropic-opus-5-5) stops a long answer at kagent's built-in 8192 tokens, thinking included. The default ModelConfig has 32000: the platform manager sets kagent.providers.anthropic.config.maxTokens for every installation (giantswarm/giantswarm-platform-manager#206), and the connectivity release already receives that value; only the default ModelConfig used it.

Change

• An Anthropic entry inherits kagent.providers.anthropic.config.maxTokens the way it already inherits promptCaching/cacheTTL, in the same provider block next to the listener baseUrl.
• An entry's own maxTokens wins and lands in its provider's block (Anthropic, AnthropicVertexAI, AzureOpenAI, Mistral, OpenAI: the ModelConfigSpec blocks that have the field). On any other provider the render fails naming the entry, instead of the API server pruning it silently.
• The chart alone invents no default.
• make verify-max-tokens asserts inheritance, precedence, the no-default case and the guard. verify-kagent-crds validates an entry with maxTokens against the kagent line's CRD.

No values change is needed on any installation: the four Opus agents get 32000 on the next rollout.

Verification

• make verify-max-tokens verify-prompt-caching verify-llm-routing verify-kagent-crds pass locally.
• After release: the Opus ModelConfigs report spec.anthropic.maxTokens: 32000, and a long Opus turn runs past 8192 tokens.

[circleci-architect]

Published Helm chart agent-platform

4.84.1-r79a95826t20260926153617ha980ae9

Chart	agent-platform
Version	4.84.1-r79a95826t20260926153617ha980ae9
OCI reference	oci://gsoci.azurecr.io/charts/giantswarm/agent-platform:4.84.1-r79a95826t20260926153617ha980ae9
Digest	sha256:90d8a01e01b2318d5aec4759b4994c49eba048ba66c94ca04c7678df768e1a1d
Registry	public — gsoci.azurecr.io
Git catalog	giantswarm-test-catalog (index)

Pull this chart

helm pull oci://gsoci.azurecr.io/charts/giantswarm/agent-platform --version 4.84.1-r79a95826t20260926153617ha980ae9

_{Posted by architect-orb · build 14938 · commit a980ae9 · updated in place on every push}

[circleci-architect]

Published Helm chart agent-platform-connectivity

4.84.1-r79a95826t20260926153617ha980ae9

Chart	agent-platform-connectivity
Version	4.84.1-r79a95826t20260926153617ha980ae9
OCI reference	oci://gsoci.azurecr.io/charts/giantswarm/agent-platform-connectivity:4.84.1-r79a95826t20260926153617ha980ae9
Digest	sha256:5ca6ea2dbe54519752f1441f5bc788841a9e6d0bf35e04d82d90563918d97a15
Registry	public — gsoci.azurecr.io
Git catalog	giantswarm-test-catalog (index)

Pull this chart

helm pull oci://gsoci.azurecr.io/charts/giantswarm/agent-platform-connectivity --version 4.84.1-r79a95826t20260926153617ha980ae9

_{Posted by architect-orb · build 14937 · commit a980ae9 · updated in place on every push}

[teemow]

From Timo's agent: agentlab proof on this branch (platform.chartPath, both charts from the checkout; the connectivity chart pushed to the lab registry as sha256:31ee3b5b and run by HelmRelease agent-platform-connectivity 1.1.35+31ee3b5be0c0). The values overlay mirrors an installation: kagent.providers.anthropic.config.maxTokens: 32000 plus one catalog entry anthropic-opus-5 without its own bound.

NAME                   MODEL               MAXTOK   CACHE
anthropic-opus-5       claude-opus-5       32000    true
default-model-config   claude-sonnet-4-6   32000    true

The API server admitted the inherited maxTokens next to the inherited promptCaching (not pruned). agentlab platform-test passes.