Custom provider models missing from /model TUI picker provider sections in 1.18.10 — caused by recents filter

Summary

Custom provider models are still missing from the provider sections of the /model TUI picker in 1.18.10, even though they load correctly. This reproduces the symptoms of closed issues #6169 / #9520 and adds evidence for the root cause: models that appear in the picker's "Recent" list are filtered out of their provider section.

Environment

• opencode 1.18.10 (installed via Homebrew, macOS, darwin arm64)
• Config: two custom providers (deepseek, minimax) using "npm": "@ai-sdk/anthropic" with baseURL + apiKey
• No project-level config; global ~/.config/opencode/opencode.json

Reproduction

1. Define custom providers with models in ~/.config/opencode/opencode.json:

{
  "provider": {
    "deepseek": {
      "npm": "@ai-sdk/anthropic",
      "options": { "apiKey": "...", "baseURL": "https://example.com" },
      "models": { "deepseek-v4-flash": { "name": "deepseek-v4-flash" } }
    },
    "minimax": {
      "npm": "@ai-sdk/anthropic",
      "options": { "apiKey": "...", "baseURL": "https://example.com" },
      "models": { "MiniMax-M3": { "name": "minimax-m3" } }
    }
  }
}

2. opencode models — all custom models are listed correctly (verified): deepseek/deepseek-v4-flash, minimax/MiniMax-M3.
3. Open the TUI, invoke /model — the custom provider sections show only models.dev built-in models (deepseek/deepseek-chat, deepseek/deepseek-reasoner, deepseek/deepseek-v4-pro, minimax/MiniMax-M2, ...). The configured custom models are absent from their provider sections.
4. Typing a search query in the picker does find the custom model; selecting it works and it appears under "Recent".

Root-cause evidence

~/.local/state/opencode/model.json (~/.cache/opencode/models.json on Linux) contains the recents/favorites state. Once a custom model is used and lands in "recent", it disappears from its provider section in the picker — matching the filtering logic that motivated the fix in #15025 (show models in provider section even when in recents/favorites), which is evidently incomplete for this case.

Workaround that confirms the mechanism: deleting ~/.local/state/opencode/model.json (backup first) temporarily restores all custom models to their provider sections. The bug recurs as soon as the model is used again and re-enters recents.

Expected behavior

Every model reported by opencode models (including custom provider models in recents/favorites) should be visible in the /model picker under its provider section.

Actual behavior

Custom provider models are only reachable via search results and the Recent section; they are absent from the provider group listings.

Workarounds (for other users)

• Delete ~/.local/state/opencode/model.json (macOS) / ~/.cache/opencode/models.json (Linux) to restore provider-section visibility temporarily.
• Set "model": "provider/model-id" in config to make a custom model the session default without touching the picker.
• Use picker search — custom models are still selectable there.