coder(providers): fix empty picker (loading-state) + config model overrides + current Claude models

Fix: getProviderSnapshot returned synchronous installed:false 'loading' entries on a cache miss (v2.5.5/Phase 2), which AgentComposerBar filters out — with the Phase 5 client poll not yet built, a single fetch stranded on 'loading' and the picker showed no providers. It now awaits the build and returns terminal entries; the sync loading-return is deferred until Phase 5. Builds stay fast via the tier-2 cold-probe skip.

Feature: wire the v2.3 config schema's models/additionalModels — buildResolvedRegistry carries them onto ResolvedProviderDef (models replace, additionalModels merge) and provider-snapshot applies them to every ready model list, so /data/coder-providers.json can edit any provider's models with no code change. Claude staticModels bumped from the stale 2-entry list to opus/sonnet/haiku latest-aliases + pinned claude-opus-4-8 / claude-sonnet-4-6 / claude-haiku-4-5-20251001 (passed verbatim to claude --model). +2 tests (109 total).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/coder/src/services/provider-config-registry.ts

@@ -22,6 +22,10 @@ export interface ResolvedProviderDef extends ProviderDef {
   env: Record<string, string> | undefined;
   configLabel?: string;
   configDescription?: string;
+  /** Config `models` — REPLACES the discovered/static model list when present. */
+  configModels?: Array<{ id: string; label: string }>;
+  /** Config `additionalModels` — MERGED on top of the resolved model list. */
+  configAdditionalModels?: Array<{ id: string; label: string }>;
 }
 
 /**
@@ -61,6 +65,8 @@ export function buildResolvedRegistry(
       env: ov?.env,
       configLabel: ov?.label,
       configDescription: ov?.description,
+      configModels: ov?.models,
+      configAdditionalModels: ov?.additionalModels,
     });
   }
 
@@ -87,6 +93,8 @@ export function buildResolvedRegistry(
       env: ov.env,
       configLabel: ov.label,
       configDescription: ov.description,
+      configModels: ov.models,
+      configAdditionalModels: ov.additionalModels,
     });
   }