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-snapshot.ts

@@ -85,6 +85,16 @@ async function buildProviderEntry(
   const label = agentRow?.label ?? resolved.configLabel ?? resolved.label;
   const descr = resolved.configDescription ? { description: resolved.configDescription } : {};
 
+  // v2.3: config `models` REPLACES the discovered/static list; `additionalModels`
+  // MERGES on top. Applied to every ready/installed model list below.
+  const withConfigModels = (m: ProviderModel[]): ProviderModel[] => {
+    let out = resolved.configModels && resolved.configModels.length > 0 ? resolved.configModels : m;
+    if (resolved.configAdditionalModels && resolved.configAdditionalModels.length > 0) {
+      out = mergeModels(out, resolved.configAdditionalModels);
+    }
+    return out;
+  };
+
   // ACP built-ins fall back to PTY transport when the installed binary lacks ACP.
   let transport = resolved.transport;
   if (agentRow && resolved.transport === 'acp' && !agentRow.supports_acp) {
@@ -104,7 +114,7 @@ async function buildProviderEntry(
   if (isNative) {
     return {
       name, label: resolved.label, transport, status: 'ready',
-      enabled: true, installed: true, models: llamaModels, modes: [],
+      enabled: true, installed: true, models: withConfigModels(llamaModels), modes: [],
       defaultModeId: null, commands: manifestCommands,
     };
   }
@@ -137,7 +147,7 @@ async function buildProviderEntry(
   if (name === 'claude') {
     return {
       name, label, transport, status: 'ready', enabled: true, installed: true,
-      models: attachClaudeThinking(models), modes: fallbackModes, defaultModeId,
+      models: attachClaudeThinking(withConfigModels(models)), modes: fallbackModes, defaultModeId,
       commands: manifestCommands,
     };
   }
@@ -165,7 +175,7 @@ async function buildProviderEntry(
       }
       return {
         name, label, transport, status: 'ready', enabled: true, installed: true,
-        models: skipModels, modes: fallbackModes, defaultModeId, commands: manifestCommands,
+        models: withConfigModels(skipModels), modes: fallbackModes, defaultModeId, commands: manifestCommands,
       };
     }
 
@@ -188,7 +198,7 @@ async function buildProviderEntry(
       name, label, transport,
       status: probe.ok ? 'ready' : 'error',
       enabled: true, installed: true,
-      models: probeModels,
+      models: withConfigModels(probeModels),
       modes: probe.modes.length > 0 ? probe.modes : fallbackModes,
       defaultModeId: probe.defaultModeId ?? defaultModeId,
       commands: mergeCommands(manifestCommands, probe.commands),
@@ -203,27 +213,10 @@ async function buildProviderEntry(
   }
   return {
     name, label, transport, status: 'ready', enabled: true, installed: true,
-    models, modes: fallbackModes, defaultModeId, commands: manifestCommands,
+    models: withConfigModels(models), modes: fallbackModes, defaultModeId, commands: manifestCommands,
   };
 }
 
-/** Synchronous placeholder entries for a cache-miss while the build runs (§4.4). */
-function loadingEntries(): ProviderSnapshotEntry[] {
-  return [...getResolvedRegistry().values()].map((r) => ({
-    name: r.id,
-    label: r.configLabel ?? r.label,
-    ...(r.configDescription ? { description: r.configDescription } : {}),
-    transport: r.transport,
-    status: r.enabled ? ('loading' as const) : ('unavailable' as const),
-    enabled: r.enabled,
-    installed: false,
-    models: [],
-    modes: getManifestModes(r.id),
-    defaultModeId: getManifestDefaultModeId(r.id),
-    commands: getManifestCommands(r.id),
-  }));
-}
-
 const snapshotCache = new Map<string, { at: number; entries: ProviderSnapshotEntry[] }>();
 const snapshotInflight = new Map<string, Promise<ProviderSnapshotEntry[]>>();
 const CACHE_TTL_MS = 5 * 60_000;
@@ -269,14 +262,13 @@ export async function getProviderSnapshot(
   });
   snapshotInflight.set(cacheKey, promise);
 
-  // force → await the full build (cold probes included). Non-force cache miss →
-  // return loading entries synchronously; the build settles in the background
-  // and the next call returns it via cache / inflight (§4.4; client polls).
-  if (force) return promise;
-  promise.catch(() => {
-    /* settled errors surface on the next call that awaits inflight/rebuilds */
-  });
-  return loadingEntries();
+  // Await the build (force or cache-miss) and return terminal entries. The sync
+  // `loading` return (design §4.4) is DEFERRED until Phase 5 ships the client
+  // poll that resolves it: without that poll, a single fetch lands on
+  // installed:false `loading` entries, which AgentComposerBar filters out
+  // (`e.installed && ...`) → empty picker. Builds stay fast via the tier-2 skip
+  // once available_agents.models is warm.
+  return promise;
 }
 
 export function clearProviderSnapshotCache(): void {