refactor: make src/llm/ self-contained for crate extraction (#767)

* refactor: make src/llm/ self-contained for crate extraction

Move LlmError, LLM config types, and OAuth callback helpers into
src/llm/ so the module has zero `use crate::` imports outside of
crate::llm. This prepares the module for extraction into a standalone
workspace crate.

- Move LlmError enum from src/error.rs to src/llm/error.rs
- Move LlmConfig, NearAiConfig, RegistryProviderConfig, BedrockConfig,
  CacheRetention, OAUTH_PLACEHOLDER from src/config/llm.rs to
  src/llm/config.rs
- Move OAuth callback utilities (callback_url, bind_callback_listener,
  wait_for_callback, landing_html, etc.) from src/cli/oauth_defaults.rs
  to src/llm/oauth_helpers.rs
- Remove session.rs dependency on crate::bootstrap (inline default path)
- Add cache_retention field to RegistryProviderConfig, resolve from env
  in config/llm.rs instead of reading env var in llm/mod.rs
- Add Check 6 to scripts/check-boundaries.sh enforcing LLM isolation
- All original locations re-export for backward compatibility

[skip-regression-check]

Co-Authored-By: Claude Opus 4.6 <[email protected]>

* style: fix formatting

Co-Authored-By: Claude Opus 4.6 <[email protected]>

* fix: address PR #767 review — session path bug and boundary check

1. Fix SessionConfig::default() usage in setup wizard: the fallback at
   wizard.rs:995 now constructs SessionConfig with the real
   default_session_path() instead of a relative "session.json", which
   would write auth tokens to the CWD instead of ~/.ironclaw/.

2. Widen check-boundaries.sh Check 6 to catch all `crate::` references
   (not just `use crate::` imports). Pre-existing inline references
   (16 occurrences) are reported as warnings; only new `use crate::`
   imports are hard violations.

[skip-regression-check]

Co-Authored-By: Claude Opus 4.6 <[email protected]>

* fix: address PR #767 review and audit findings in src/llm/

PR review fixes:
- Reject wildcard addresses (0.0.0.0, ::) in OAuth callback listener
  to prevent session token exposure on all interfaces
- Fix boundary check comment-stripping that could hide real violations
  (use sed to strip inline comments before matching)

Audit fixes:
- Fix UTF-8 byte-index slicing panic in recording.rs hint extraction
- Add effective_model_name() delegation to RetryProvider and
  SmartRoutingProvider for consistency with other wrappers
- Add calculate_cost() delegation to CachedProvider and RecordingLlm
- Deduplicate retry loop logic in RetryProvider via generic helper
- Replace hardcoded /tmp path in recording tests with tempfile

Co-Authored-By: Claude Opus 4.6 <[email protected]>

---------

Co-authored-by: Claude Opus 4.6 <[email protected]>

src/setup/wizard.rs

@@ -22,7 +22,7 @@ use crate::bootstrap::ironclaw_base_dir;
 use crate::channels::wasm::{
     ChannelCapabilitiesFile, available_channel_names, install_bundled_channel,
 };
-use crate::config::llm::OAUTH_PLACEHOLDER;
+use crate::config::OAUTH_PLACEHOLDER;
 use crate::llm::{SessionConfig, SessionManager};
 use crate::secrets::{SecretsCrypto, SecretsStore};
 use crate::settings::{KeySource, Settings};
@@ -992,7 +992,10 @@ impl SetupWizard {
         let session = if let Some(ref s) = self.session_manager {
             Arc::clone(s)
         } else {
-            let config = SessionConfig::default();
+            let config = SessionConfig {
+                session_path: crate::config::llm::default_session_path(),
+                ..SessionConfig::default()
+            };
             Arc::new(SessionManager::new(config))
         };
 
@@ -1588,7 +1591,7 @@ impl SetupWizard {
             backend: "nearai".to_string(),
             session: crate::llm::session::SessionConfig {
                 auth_base_url,
-                session_path: crate::llm::session::default_session_path(),
+                session_path: crate::config::llm::default_session_path(),
             },
             nearai: crate::config::NearAiConfig {
                 model: "dummy".to_string(),
@@ -2552,7 +2555,7 @@ impl SetupWizard {
     /// Best-effort: silently ignores errors (no DB connection yet, no
     /// session file, etc.).
     async fn persist_session_to_db(&self) {
-        let session_path = crate::llm::session::default_session_path();
+        let session_path = crate::config::llm::default_session_path();
         let data = match std::fs::read_to_string(&session_path) {
             Ok(d) if !d.trim().is_empty() => d,
             _ => return,
@@ -2861,7 +2864,7 @@ async fn fetch_anthropic_models(cached_key: Option<&str>) -> Vec<(String, String
     let api_key = cached_key
         .map(String::from)
         .or_else(|| std::env::var("ANTHROPIC_API_KEY").ok())
-        .filter(|k| !k.is_empty() && k != crate::config::llm::OAUTH_PLACEHOLDER);
+        .filter(|k| !k.is_empty() && k != crate::config::OAUTH_PLACEHOLDER);
 
     // Fall back to OAuth token if no API key
     let oauth_token = if api_key.is_none() {