Extract config structs into pkg/probodconfig

probod-bootstrap only needs the config struct definitions for
YAML marshaling but transitively pulled in ~40 heavy runtime
dependencies via pkg/probod. Move all config types and their
methods to a new pkg/probodconfig package and re-export them
from pkg/probod via type aliases for backward compatibility.

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/probodconfig/llm_config.go

@@ -0,0 +1,71 @@
+// Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+package probodconfig
+
+type (
+	// LLMProviderConfig holds authentication and connection settings for an
+	// LLM provider (e.g. OpenAI, Anthropic).
+	LLMProviderConfig struct {
+		Type   string `json:"type"`    // "openai", "anthropic", "bedrock"
+		APIKey string `json:"api-key"` // for OpenAI and Anthropic
+	}
+
+	// LLMAgentConfig holds model parameters for a single agent. Provider
+	// references one of the keys in AgentsConfig.Providers.
+	LLMAgentConfig struct {
+		Provider    string   `json:"provider"` // key into AgentsConfig.Providers
+		ModelName   string   `json:"model-name"`
+		Temperature *float64 `json:"temperature"`
+		MaxTokens   *int     `json:"max-tokens"`
+	}
+
+	// EvidenceDescriberConfig holds worker-side tuning for the evidence
+	// description background worker. LLM parameters for the same worker
+	// live under AgentsConfig.EvidenceDescriber.
+	EvidenceDescriberConfig struct {
+		Interval       int `json:"interval"`    // seconds between polls
+		StaleAfter     int `json:"stale-after"` // seconds before a claim is recycled
+		MaxConcurrency int `json:"max-concurrency"`
+	}
+
+	// AgentsConfig groups LLM provider credentials and per-agent model
+	// settings. Default is used as a fallback when an agent-specific field
+	// is zero-valued.
+	AgentsConfig struct {
+		Providers         map[string]LLMProviderConfig `json:"providers"`
+		Default           LLMAgentConfig               `json:"defaults"`
+		Probo             LLMAgentConfig               `json:"probo"`
+		EvidenceDescriber LLMAgentConfig               `json:"evidence-describer"`
+		VendorAssessor    LLMAgentConfig               `json:"vendor-assessor"`
+	}
+)
+
+// ResolveAgent returns a fully populated LLMAgentConfig by filling in
+// zero-valued fields from the default config.
+func (c *AgentsConfig) ResolveAgent(agent LLMAgentConfig) LLMAgentConfig {
+	if agent.Provider == "" {
+		agent.Provider = c.Default.Provider
+	}
+	if agent.ModelName == "" {
+		agent.ModelName = c.Default.ModelName
+	}
+	if agent.Temperature == nil {
+		agent.Temperature = c.Default.Temperature
+	}
+	if agent.MaxTokens == nil {
+		agent.MaxTokens = c.Default.MaxTokens
+	}
+	return agent
+}