fix(custom-model): core review fixes for context-length discovery and injection

- share one context-length resolution (discovered figure, endpoint default fallback) across the routes and boot recovery, with a recovery test
- record listed per-slot context figures with a slot count of 1 and force the slot-count fallback once per rediscovery
- open up the codex model launch token for qwen3-style ids (model-plain-colon), pinned by a spawn-golden case
- pass the full discovered window to opencode as limit.context
- translate the picker search strings and document the discovery precedence

src/config/cli-registry/patterns.ts

@@ -21,6 +21,7 @@ export type TokenPattern =
   | 'model'
   | 'model-claude'
   | 'model-plain'
+  | 'model-plain-colon'
   | 'model-pi'
   | 'id'
   | 'id-dotted'
@@ -47,6 +48,10 @@ const PATTERNS: Record<TokenPattern, RegExp> = {
   // copilot --model. Same characters as `model`, but a leading alphanumeric: the value follows a
   // flag, so `--yolo` must not pass as a model id and become its own flag (the allowAll clamp bypass).
   'model-plain': /^[a-zA-Z0-9][a-zA-Z0-9._\-/]*$/,
+  // codex --model, and the value a custom-model `launchModel` is forced onto it. Same
+  // shape as `model-plain` (leading alphanumeric, so a flag cannot ride the flag) plus
+  // `:` — Ollama-style ids like `qwen3:32b` must survive onto the command line.
+  'model-plain-colon': /^[a-zA-Z0-9][a-zA-Z0-9._\-/:]*$/,
   // buildPiCommand — `:` for a thinking suffix (`sonnet:high`), `/` for `provider/id`
   'model-pi': /^[a-zA-Z0-9._\-/:]+$/,
   // opencode --session, codex resume

src/config/cli-registry/stock.ts

@@ -628,7 +628,10 @@ const CODEX: CliEntry = {
     params: {
       bypassApprovals: { type: 'bool' },
       animations: { type: 'bool' },
-      model: { type: 'token', pattern: 'model' },
+      // `model-plain-colon`, not `model`: the custom-model feature forces the selected id
+      // onto this param (`launchModel: '{modelId}'` below), and Ollama-style ids carry a
+      // `:` (`qwen3:32b`). A leading alphanumeric still keeps `--yolo` from riding a flag.
+      model: { type: 'token', pattern: 'model-plain-colon' },
       reasoningEffort: { type: 'enum', values: [...CODEX_REASONING_EFFORTS] },
       resumeId: { type: 'token', pattern: 'id' },
     },
@@ -1922,8 +1925,8 @@ const COPILOT: CliEntry = {
     // custom provider and drops the GitHub sign-in requirement; COPILOT_PROVIDER_TYPE defaults to
     // "openai", which is what a Codeman custom endpoint is (llama.cpp, vLLM, Ollama).
     // COPILOT_MODEL names the model and COPILOT_PROVIDER_MODEL_ID / _WIRE_MODEL default to it.
-    // The OpenAI-style route is `<base>/v1/chat/completions`, so the base gets the `/v1` suffix
-    // the same way deepseek's does. All four already match the COPILOT_ prefix allowlist, so
+    // The OpenAI-style route is `<base>/v1/chat/completions`, so the base gets the `/v1`
+    // suffix via appendV1Suffix below. All four already match the COPILOT_ prefix allowlist, so
     // they are privileged env keys below: a non-granted multi-user owner must not be able to
     // redirect the session's endpoint or credentials through plain envOverrides.
     customModelInjection: {

src/config/cli-registry/types.ts

@@ -856,19 +856,13 @@ export interface CliCapabilities {
    * reuses that file.
    *
    * `appendV1Suffix` (env kind only): the raw `endpoint.baseUrl` gets `withV1Suffix()`
-   * applied before being written to `baseUrlVar`, instead of being used verbatim.
-   * DeepSeek needs this and claude/gemini must NOT get it — a per-CLI asymmetry confirmed
-   * by reading each SDK's own request-building source, not assumed: DeepSeek Harness's
-   * bundled `@deepseek-ai/dsh-llm-deepseek` concatenates `${connection.baseURL}/chat/
-   * completions` with no `/v1` insertion of its own (its real public API base,
-   * `https://api.deepseek.com`, expects the caller's base URL to already carry any
-   * needed prefix), while llama-swap/llama.cpp only ever serves the OpenAI-conventional
-   * `/v1/chat/completions` — confirmed live: a bare `POST <baseUrl>/chat/completions`
-   * 404s, `POST <baseUrl>/v1/chat/completions` succeeds, and the harness's own error
-   * message template (`DeepSeek API error (HTTP ${status})`) reproduces the exact
-   * `HTTP_404` this feature originally shipped with unexplained. Claude Code's own SDK,
-   * by contrast, was already confirmed working end-to-end against the RAW `baseUrl` with
-   * no suffix — appending one there would be wrong, not just redundant.
+   * applied before being written to `baseUrlVar`, instead of being used verbatim. Only
+   * deepseek and copilot declare it — both speak to `<base>/v1/chat/completions` and a
+   * gateway saves the bare root. claude/gemini must NOT get it: Claude Code's own SDK was
+   * confirmed working end-to-end against the RAW `baseUrl`, so appending a suffix there
+   * would be wrong, not just redundant. The per-session config-file recipes do not need
+   * this flag at all — `renderConfigFile()` applies the suffix inside every template, so
+   * no configDir entry carries a raw base URL.
    */
   customModelInjection:
     | {