fix(custom-model): give a session its own env values back when the selection goes

Applying a custom model writes the endpoint's values over the keys it
injects, and clearing the model unset those keys. A session that had set
one of them itself lost that value: its own DSH_HOME, CODEX_HOME,
GROK_HOME or GEMINI_API_KEY was gone once the model was cleared, and so
was CLAUDE_CONFIG_DIR, which silently moved a Claude session onto the
default account. Switching endpoints did the same.

setCustomModel() now records what the session held under each injected
key and restores it on clear and on switch. Quick-start passes the
caller's values to the Session constructor so they are seen before the
selection lands.

The selection overwrites the only other copy, tmux's setenv, so the
session's own home directory has to survive a Codeman restart on its
own. __customModel therefore stores that one path, the single exception
to persisting keys only, and recovery runs it through
clampEnvOverridesForOwner() so a revoked grant cannot bring it back. Any
other own value, a credential included, stays in memory only.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/architecture-invariants.md

@@ -638,7 +638,7 @@ Adding the header changed the preamble, so `CODEMAN_PREAMBLE` was bumped (1.22.0
 
 ⚠️ The actual per-CLI redirect is `capabilities.customModelInjection` on the CLI registry (four kinds: `env` for claude/gemini/copilot, `configContentEnv` reusing opencode's existing `OPENCODE_CONFIG_CONTENT`, `configDir` for codex/pi/grok/omp/deepseek, writes an isolated per-session config file, NEVER the user's real `~/.codex`/`~/.pi`/`~/.omp`/grok config/dsh home; deepseek's redirect is a per-session `DSH_HOME` holding only the generated `cordis.patch.yml`, whose `linkFromRealHome` recipe field symlinks `profiles`/`sessions`/`settings.yaml` back out of the real dsh home (resolved session-`DSH_HOME`-first, lstat-guarded so a dangling link survives re-apply) instead of stranding them, and `unsupported` for antigravity, which has no known mechanism), computed by the pure `custom-model-injection.ts` (mirrors `session-cli-builder.ts`'s no-IO discipline). ⚠️ `PI_CONFIG_DIR` does NOTHING for pi or omp (grepped pi's entire bundled JS source, the string appears nowhere); both hardcode `~/.pi/agent/models.json` / `~/.omp/agent/models.yml` with no dedicated override, so the real redirect for both is the child process's own **`HOME`**, and both need `models` as an ARRAY of `{id}` objects (an object keyed by id silently loads zero models). Grok's real mechanism turned out to be a `config.toml` `[model.<name>]` block redirected via `GROK_HOME`, its original env-var-based recipe was flat-out wrong (produced "Not signed in" against a real binary), not just unverified.
 
-⚠️ **Two launch paths, chosen by mechanism, not preference**: opencode/codex/gemini/pi/grok/deepseek/omp apply the selection ONE-SHOT, before the session/process ever exists, with no restart at all; claude alone still applies a selection by **restarting the session's CLI process in place** via `Session.restartCli()`, a de-restricted `reattachRemote()` reusing the same `respawn-pane -k` primitive local/remote respawns already share, because every one of these harnesses reads its endpoint config at process start, never per-turn, so there is no live hot-swap; `Session.setCustomModel()` undoes the PREVIOUS selection's env keys (and deletes its old `configDir`) before merging the new ones in, so switching endpoints or clearing back to native cloud never leaves a stale key behind. ⚠️ Deleting a key from `_envOverrides` is NOT enough on its own: `tmux setenv` persists at the tmux-session level and is inherited by `respawn-pane` (measured: `setenv FOO bar` survived two successive `respawn-pane -k`), so the retired keys are queued (`_pendingEnvUnsets`) and ride `RespawnPaneOptions.unsetEnvKeys` into `applyEnvOverrides()`, which `setenv -u`s them BEFORE re-applying the live overrides. ⚠️ `restartCli()` relaunches a CLI in an existing pane, so a CLI whose launch declares a `fallback` chain (claude) gets a conversation pinned as `resumeSessionId` for that one respawn: `--session-id <id>` refuses an id that already has a transcript (`Session ID ... is already in use`), and without the `--resume <id> || --session-id <id>` shape the docker/remote pane commands already use, applying a model killed the pane and lost the session. The dead-pane respawn shares this pin, see [Dead-pane respawn: the resume pin](#dead-pane-respawn-the-resume-pin). ⚠️ pi, omp and grok need the config file AND a `model` launch param (`custom/<id>` for pi/omp, grok's `[model.codeman-custom]` block name), and codex gets one too (`--model <bare modelId>`, its pattern changed to `model-plain-colon`, which admits qwen3-style colon ids and requires a letter or digit first, for the native App Settings Codex model too): that is the registry's `customModelInjection.launchModel` template, applied onto the respawn options through `legacyConfigField` by `_withCustomModelLaunchModel()`, never by id, and a model id the CLI's `model` token pattern cannot carry is refused with a 400 rather than silently dropped by the argv engine. ⚠️ Remote (SSH) and Docker sessions are REFUSED (400): their `restartCli()` reattaches a durable tmux rather than restarting the agent and the env lands on the local pane, so they used to report `restarted:true` and change nothing. The selection survives a Codeman restart as the disk-only `__customModel` (bookkeeping: env KEYS, config dir, launch model; never the values, which carry the API key and are re-derived from the endpoint store on recovery), the config dir is removed with the session, and every secret-bearing file (`custom-model-hosts.json`, the per-session config dir) is written 0600.
+⚠️ **Two launch paths, chosen by mechanism, not preference**: opencode/codex/gemini/pi/grok/deepseek/omp apply the selection ONE-SHOT, before the session/process ever exists, with no restart at all; claude alone still applies a selection by **restarting the session's CLI process in place** via `Session.restartCli()`, a de-restricted `reattachRemote()` reusing the same `respawn-pane -k` primitive local/remote respawns already share, because every one of these harnesses reads its endpoint config at process start, never per-turn, so there is no live hot-swap; `Session.setCustomModel()` undoes the PREVIOUS selection's env keys (and deletes its old `configDir`) before merging the new ones in, so switching endpoints or clearing back to native cloud never leaves a stale key behind. It also puts back what the session had set itself under an injected key (`CustomModelBookkeeping.ownEnv`, read after the undo so a switch carries it across): an own `DSH_HOME` or `CLAUDE_CONFIG_DIR` used to be deleted with the injected value, which moved the session to the server's tree or the default Claude account. ⚠️ `ownEnv` can hold a credential in memory, so `getCustomModelForPersist()` writes only its `homeEnvVar` entry, a path, which it must write because the selection overwrote the tmux `setenv` that was the only other copy. `_restoreCustomModel()` always states `ownEnv` (empty for an older record) after `clampEnvOverridesForOwner()`: after a restart `_envOverrides` holds what the previous run INJECTED, and reading that as the session's own would pin it to a directory the clear deletes. Quick-start hands the `Session` constructor the caller's overrides alone so `setCustomModel()` can see them. ⚠️ Deleting a key from `_envOverrides` is NOT enough on its own: `tmux setenv` persists at the tmux-session level and is inherited by `respawn-pane` (measured: `setenv FOO bar` survived two successive `respawn-pane -k`), so the retired keys are queued (`_pendingEnvUnsets`) and ride `RespawnPaneOptions.unsetEnvKeys` into `applyEnvOverrides()`, which `setenv -u`s them BEFORE re-applying the live overrides. ⚠️ `restartCli()` relaunches a CLI in an existing pane, so a CLI whose launch declares a `fallback` chain (claude) gets a conversation pinned as `resumeSessionId` for that one respawn: `--session-id <id>` refuses an id that already has a transcript (`Session ID ... is already in use`), and without the `--resume <id> || --session-id <id>` shape the docker/remote pane commands already use, applying a model killed the pane and lost the session. The dead-pane respawn shares this pin, see [Dead-pane respawn: the resume pin](#dead-pane-respawn-the-resume-pin). ⚠️ pi, omp and grok need the config file AND a `model` launch param (`custom/<id>` for pi/omp, grok's `[model.codeman-custom]` block name), and codex gets one too (`--model <bare modelId>`, its pattern changed to `model-plain-colon`, which admits qwen3-style colon ids and requires a letter or digit first, for the native App Settings Codex model too): that is the registry's `customModelInjection.launchModel` template, applied onto the respawn options through `legacyConfigField` by `_withCustomModelLaunchModel()`, never by id, and a model id the CLI's `model` token pattern cannot carry is refused with a 400 rather than silently dropped by the argv engine. ⚠️ Remote (SSH) and Docker sessions are REFUSED (400): their `restartCli()` reattaches a durable tmux rather than restarting the agent and the env lands on the local pane, so they used to report `restarted:true` and change nothing. The selection survives a Codeman restart as the disk-only `__customModel` (bookkeeping: env KEYS, config dir, launch model; never the values, which carry the API key and are re-derived from the endpoint store on recovery), the config dir is removed with the session, and every secret-bearing file (`custom-model-hosts.json`, the per-session config dir) is written 0600.
 
 ⚠️ **Security**: every env var this feature can redirect (`ANTHROPIC_BASE_URL`, `GOOGLE_GEMINI_BASE_URL`, `CODEX_HOME`, `GROK_HOME`, `HOME` for pi/omp, `OPENCODE_CONFIG_CONTENT`, etc.) is in that CLI's `privilegedEnvKeys` — several of these were reachable via the generic `envOverrides` field's prefix allowlist BEFORE this feature existed (the env allowlist is global and prefix-based, not per-CLI-scoped), so building this surfaced and closed a pre-existing gap rather than opening a new one. `ANTHROPIC_*` is deliberately NOT in claude's `allowedPrefixes` at all — Anthropic-traffic redirection can only happen through this feature's own admin-configured, SSRF-guarded route, never a plain client-supplied `envOverrides`.
 

docs/custom-model-endpoints.md

@@ -535,13 +535,19 @@ id, model and injected key NAMES are persisted, the values are re-derived
 from the endpoint store on recovery, and the pane keeps running against the
 endpoint in between because tmux retains its environment.
 
-⚠️ Clearing removes injected keys **by name**, and `CLAUDE_CONFIG_DIR` is one
-of the names claude's selection injects — so a session that ALSO had
-`CLAUDE_CONFIG_DIR` set through the generic `envOverrides` field (the
-per-client-account case) loses that override on clear too, and silently
-falls back to the server's default Claude account. If you route a session
-to a specific account this way, re-apply the override after clearing a
-custom-model selection from it.
+A value the session set itself under an injected key comes back when the
+selection goes, on a clear or a switch to another endpoint. That is what
+keeps a session on its own `DSH_HOME`, `CODEX_HOME` or `GROK_HOME`, and on
+its own account through `CLAUDE_CONFIG_DIR` (the per-client-account case).
+
+⚠️ Across a Codeman restart only the home directory comes back. The
+selection overwrote the tmux `setenv` that held it, so its record in
+`state.json` keeps that one path (`ownEnv`), and a non-granted owner loses it
+at recovery like any other privileged override. Any other own value can be a
+credential and stays in memory: a session that set its own `GEMINI_API_KEY`,
+picked an endpoint and then outlived a restart falls back to the server's key
+on clear. A selection saved by an older build has no such record, so its first
+clear still falls back to the server's default.
 
 **New sessions always default back to the harness's native backend.** A
 custom-endpoint selection is a per-session choice, never a sticky global