[Bug]: Account Models (GLM-5.3-Flash) Cannot Be Selected via App-Server Protocol Due to Revision Type Mismatch

Bug Description

In ZCode 3.12.3 (tested on macOS arm64), when using zcode.cjs app-server over stdio in hosted mode, account models (e.g. GLM-5.3-Flash under account:zai-individual-coding-plan) cannot be selected via the RPC protocol:

session/setModel {
  "model": {
    "providerId": "account:zai-individual-coding-plan",
    "modelId": "GLM-5.3-Flash"
  }
}

Error Returned:
→ -32603 Provider Registry 中不存在 Model

Additionally, turns initiated via session/send with a modelSelection override stall indefinitely with a provider_not_found event.

Root Cause Analysis (Confirmed via Bundle Disassembly)

1. The desktop chat engine runs in standalone mode (initializing account providers directly from local credential stores).
2. A CLI-spawned app-server child process runs in hosted mode, where account providers must be received via a provider/updateAccountConfig push from the host.
3. While the RPC responds with status: "received", the snapshot payload is silently discarded right before registry merge by this gate:

   if (snapshot.basedOnZCodeBuiltinRevision !== configSource.zcodeBuiltinRevision) { /* discard */ }
   

4. The Type Mismatch:
   • The incoming wire schema enforces basedOnZCodeBuiltinRevision as a string (z.string().trim()).
   • The internal configSource.zcodeBuiltinRevision is stored as a number (e.g. value 28).
   • Because of strict inequality (!==), the condition evaluates to true on 100% of payloads ("28" !== 28), guaranteeing that no snapshot can ever pass the gate and merge into the provider registry.

Environment & Reproduction

• App Version: ZCode 3.12.3 (macOS arm64)
• Execution Mode: zcode.cjs app-server (--stdio / --surface desktop)
• Reported by: 박명철 [Z.ai] on Z.ai Community Discord
• Discord Thread: https://discord.com/channels/1346756824233148527/1550166821707972658

Proposed Fix

1. Normalize Revision Comparison:
   Coerce both sides of the comparison to strings or numbers before evaluation:

   if (String(snapshot.basedOnZCodeBuiltinRevision) !== String(configSource.zcodeBuiltinRevision)) { ... }
   

2. Schema Coercion:
   Allow basedOnZCodeBuiltinRevision in the wire schema to accept z.union([z.string(), z.number()]) or apply z.coerce.number().
3. Optional Standalone Flag:
   Provide a CLI argument (e.g. --standalone-providers) allowing app-server to read credentials directly from local credential storage.

Start at the zcode.cjs app-server entry point and trace provider/updateAccountConfig handling through the revision comparison before registry merge. Reproduce the session/setModel or session/send request with the account model, then verify that the revision values compare consistently, the provider registry receives the snapshot, and no provider_not_found event occurs.