fix: strip provider prefix before matching configured default_model

[asans]

Problem

When config.provider.default_model is set to a provider-prefixed spec (e.g. claude-oauth:claude-sonnet-5, which is exactly what the model picker persists via /model -> "save as default"), running /login to re-authenticate or /refresh-model-list silently reverts the active model to the flagship default (Opus) instead of keeping the configured Sonnet model.

Root cause

provider_model_to_select_after_auth_with_configured_default in crates/jcode-base/src/auth/lifecycle.rs compares the configured default model directly against route.model from the live catalog:

if let Some(configured) = configured_model
    && routes.iter().any(|route| {
        route.available
            && route.model == configured
            && route_matches_activation(route, activation)
    })

route.model in the catalog is always the bare model id (e.g. claude-sonnet-5), but config.provider.default_model is persisted by the model picker as a full spec that may carry an explicit provider/credential prefix (e.g. claude-oauth:claude-sonnet-5, claude-api:claude-fable-5). The direct string comparison never matches when a prefix is present, so the "preserve the configured default" branch silently no-ops and falls through to the flagship-first fallback, which always prefers Opus.

The cold-start path (MultiProvider::set_config_default_model) already handles this correctly by checking explicit_model_provider_prefix before matching — this is why a fresh jcode launch respects the configured Sonnet default, but re-authenticating via /login or refreshing the catalog via /refresh-model-list does not.

Fix

Strip the provider prefix off the configured model (using the existing jcode_provider_core::selection::explicit_model_provider_prefix helper) before comparing against route.model.

Testing

• Added post_auth_model_selection_preserves_provider_prefixed_configured_default, a regression test reproducing the exact reported scenario (prefixed config default + Claude re-auth), confirmed it fails on the old code and passes with the fix.
• cargo test -p jcode-base --lib auth::lifecycle:: — 39/40 pass; the one pre-existing failure (every_model_login_provider_has_explicit_lifecycle_normalization, missing grok-build normalization) reproduces identically on master before this change and is unrelated.
• Built and reloaded onto the fixed binary via self-dev to confirm the fix at runtime.

[greptile-apps]

Confidence Score: 4/5

Not safe to merge until configured provider and credential-route constraints are retained or validated during post-authentication default-model selection.

Findings

1.  Credential Route Is Rewritten ▶

Fix with agent prompt

### Issue 1
crates/jcode-base/src/auth/lifecycle.rs:238-242
When a configured default explicitly selects `claude-api:claude-sonnet-5`, this code removes the `claude-api` credential-route prefix and accepts the bare model during a Claude OAuth login. The later selection rebuild changes it to `claude-oauth:claude-sonnet-5`, so an API-key route configured by the user is silently replaced with OAuth credentials. Preserve the configured route constraint when matching the post-authentication catalog, or do not accept the configured default when it is incompatible with the activated route.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

Summary

This change normalizes provider-prefixed configured defaults before matching them to the post-authentication model catalog. A focused check shows that this can discard an explicitly configured Claude API-key route and rebuild the default as a Claude OAuth route, so the configured credential mode is not preserved.

_{Reviews (1) · Last reviewed commit: "fix: strip provider prefix before matchi..."}

[greptile-apps]

Credential Route Is Rewritten

When a configured default explicitly selects claude-api:claude-sonnet-5, this code removes the claude-api credential-route prefix and accepts the bare model during a Claude OAuth login. The later selection rebuild changes it to claude-oauth:claude-sonnet-5, so an API-key route configured by the user is silently replaced with OAuth credentials. Preserve the configured route constraint when matching the post-authentication catalog, or do not accept the configured default when it is incompatible with the activated route.

Artifacts

Evidence from the check

• This is the full temporary Rust test source executed against the changed selection and rebuild path, showing the configured API-key route is expected to become an OAuth route.

Evidence from the check

• This is the exact shell command wrapper used to copy the temporary test into the crate, run Cargo, capture its status, and remove it afterward.

Command output from the check

• Cargo executed one focused test successfully and printed the configured, selected, and rebuilt values, confirming the explicit API-key route changed to OAuth.

_{Ran code and verified through T-Rex}

Prompt To Fix With AI

This is a comment left during a code review.
Path: crates/jcode-base/src/auth/lifecycle.rs
Line: 238-242

Comment:
**Credential Route Is Rewritten**

When a configured default explicitly selects `claude-api:claude-sonnet-5`, this code removes the `claude-api` credential-route prefix and accepts the bare model during a Claude OAuth login. The later selection rebuild changes it to `claude-oauth:claude-sonnet-5`, so an API-key route configured by the user is silently replaced with OAuth credentials. Preserve the configured route constraint when matching the post-authentication catalog, or do not accept the configured default when it is incompatible with the activated route.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.