feat(custom-model): Custom Model Endpoint Profiles (local or cloud, all harnesses)

Point any Codeman-supported harness (Claude, opencode, Codex, Gemini, Pi,
Grok, DeepSeek, OMP) at a custom OpenAI-compatible endpoint instead of its
native cloud backend, for a given session. Covers local hardware (llama.cpp,
Ollama, vLLM, DGX Spark, Strix Halo) and cloud (Azure AI Foundry, OpenRouter).
Off by default (customModelEndpointsEnabled, synced, default OFF).

- Registry: capabilities.customModelInjection per CLI entry (env /
  configContentEnv / configDir / unsupported kinds)
- Pure injection builder (custom-model-injection.ts) turning an endpoint +
  model id into the real env vars / config content per CLI
- Endpoint store + CRUD routes (custom-model-hosts.ts,
  custom-model-routes.ts), discovery via GET /v1/models, SSRF-guarded
- Session integration: Session.setCustomModel()/restartCli()
  (POST /api/sessions/:id/custom-model), reusing the existing
  respawn-pane -k primitive to restart the CLI process with new env
- Multi-user hardening: every new redirect-capable env var added to its
  CLI's privilegedEnvKeys, closing a pre-existing gap where several were
  already reachable via the generic envOverrides field's prefix allowlist
- Standalone scripts/test-local-llm-harnesses.mjs: spawns real CLI binaries
  against a real endpoint outside the web UI, independent of tmux/sessions
- Mock-server contract tests (test/fixtures/mock-openai-server.ts) replaying
  every CLI's injected values through a real HTTP shape

Real end-to-end validation against a live llama-swap server (inside a
codeman/agent:llm-test Docker image with all 9 CLI binaries) found and
fixed three real bugs before they shipped:
- Codex's config.toml schema was wrong ([model].default table instead of
  a top-level model string + [model_providers.custom]); fixing it then
  surfaced a genuine, documented protocol incompatibility (Codex only
  speaks the Responses API since Feb 2026, which llama.cpp/llama-swap
  don't implement)
- Claude Code's async session-title-generation call validates
  ANTHROPIC_DEFAULT_HAIKU_MODEL against its own internal model list and
  hangs the whole -p invocation on an unrecognized name; documented for
  chunk 6, worked around in the standalone script only (--bare is NOT
  safe for a real interactive session, which needs hooks)
- The discovery route's authStyle: 'both' option (send both Authorization
  and api-key headers) reliably hung a real server; removed the option
  entirely rather than just changing the default

Status: draft. Chunk 6 (frontend toolbar/settings UI) not yet built — see
PR.md and deployment_plan.md for the full chunk breakdown and confidence
table.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017HqNWfmtBU2KN29SvSVWB3

CLAUDE.md

@@ -225,6 +225,8 @@ Codeman is a Claude Code session manager with web interface and autonomous Ralph
 
 **DeepSeek web UI** (`POST`/`GET`/`DELETE /api/deepseek/web`, `deepseek-web-server.ts`): the Run menu's "DeepSeek web UI..." entry supervises ONE background `dsh web` child process, deliberately **NOT a shell session**. The session version worked and was still wrong in use: it put a terminal tab on screen next to the web tab the user actually asked for, every single time, and nothing about a long-lived HTTP server needs to be a tab. ⚠️ What a session gave for free now has to be paid for explicitly, and every piece is load-bearing: **exactly one** server (a second click REUSES it rather than racing it for a port, which two sessions structurally could not do), **restarted when the browser authority changes** (`--trusted-host` fences dsh's `/api` against the browser authority, and a Codeman reachable at both loopback and a tailnet name has two, so whoever asks last wins: the asker is by definition the origin about to load the page), **killed on shutdown** (`stopDeepSeekWeb()` in the server teardown, because the child is detached so its whole plugin tree can be signalled at once, which also means it would OUTLIVE Codeman and hold its port against the next start), and **failures returned to the caller**, since with no tab there is nowhere for a stack trace to land. ⚠️ The port search starts at dsh's own default 3080 and walks 40, never fixed: that default is precisely the port most likely to be taken already by the user's own `dsh web`, and hardcoding it killed this feature with EADDRINUSE once. Free-port detection BINDS rather than connects (a connect probe cannot tell "free" from "listening but not answering yet"), so it is racy by nature and the caller still waits for the server to really answer before reporting success. ⚠️ Both `POST` and `DELETE` sit at the **same privilege bar as the profile installer** (`canUsernameRunPrivilegedCommands`) even though the action reads as "open a page": booting a dsh profile executes the plugin code in it, and the server is a single shared instance, so stopping it in multi-user mode takes it out from under other users' tabs.
 
+**Custom Model Endpoint Profiles** (opt-in, `customModelEndpointsEnabled`, SYNCED, default OFF; `docs/custom-model-endpoints.md`, design doc `deployment_plan.md`): points a session at a user-configured custom OpenAI-compatible endpoint — local (llama.cpp, DGX Spark, Strix Halo) or cloud (Azure AI Foundry, OpenRouter) — instead of its harness's native cloud backend. Endpoints are a read/write-array store (`custom-model-hosts.ts`, `~/.codeman/custom-model-hosts.json`) discovered via `GET <baseUrl>/v1/models`; `CustomModelHost.authStyle` (default `'both'`) sends BOTH `Authorization: Bearer` and `api-key` headers on discovery since cloud gateways (Azure) and local servers (llama.cpp) disagree on the convention and there is no way to know in advance which one a given endpoint wants. ⚠️ The actual per-CLI redirect is `capabilities.customModelInjection` on the CLI registry (four kinds: `env` for claude/gemini/grok/deepseek, `configContentEnv` reusing opencode's existing `OPENCODE_CONFIG_CONTENT`, `configDir` for codex/pi/omp — writes an isolated per-session config file, NEVER the user's real `~/.codex`/`~/.pi` config — 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). ⚠️ Applying a selection **restarts 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. ⚠️ **Security**: every env var this feature can redirect (`ANTHROPIC_BASE_URL`, `GOOGLE_GEMINI_BASE_URL`, `CODEX_HOME`, `PI_CONFIG_DIR`, `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`. Confidence is per-CLI: claude/opencode/codex are hand-verified against a real llama.cpp/llama-swap server; gemini/pi/grok/deepseek/omp have their ONE-SHOT INVOCATION flags confirmed against real installed binaries' `--help` output, but their custom-endpoint env/config conventions remain unverified — see the confidence table in `deployment_plan.md`. The standalone `scripts/test-local-llm-harnesses.mjs` (reads a gitignored `scripts/local-llm-test.config.json`, template `.example.json` tracked) smoke-tests real CLI binaries against a real endpoint outside the web UI entirely, independent of tmux/sessions.
+
 **Run launch synchronization**: the Run entrypoint holds an in-flight lock and disables `#runBtn` for the whole launch (≥500ms), so a double click cannot create duplicate sessions with the same `w<n>-<case>` name. `_ensureCreatedSessionVisible()` runs before `selectSession()`, and `_onSessionCreated()` stays an idempotent upsert, so POST-first and SSE-first ordering both produce exactly one rendered tab. ⚠️ **Closing has the mirror-image race and one owner**: `closeSession()` reads `wasActive` BEFORE its `await` and announces the delete via `_closingSessions`, while `_onSessionDeleted` skips the active-session handoff for an id in that set. Both used to read `activeSessionId` after the fact, so the `session_deleted` broadcast for your own delete could null it first and closing the tab you were on landed on the welcome screen instead of the next session, on the same build, depending on timing. The fallback also picks the first order entry that is still in `sessions` (a dead id can linger in `sessionOrder`, same reason Alt+N indexes a live-filtered list). A delete from ANOTHER client still shows the welcome screen, which is the honest answer when what you were looking at was taken away. Tests: `test/session-close-fallback.test.ts`. → [architecture-invariants#run-launch-synchronization](docs/architecture-invariants.md#run-launch-synchronization)
 
 **Session lineage lines** (tab → tab it spawned, `sessionLineageLines`, per-device, desktop default ON): a create request may name the session that spawned it, as a `parentSessionId` body field on `POST /api/sessions` / `POST /api/quick-start` or the `X-Codeman-Parent-Session` header (the agent skill sets that once on its shared curl invocation, so every spawn recipe carries it). `resolveParentSessionId()` (route-helpers.ts) **resolves rather than trusts** it: exact id, else a UNIQUE ≥8-char prefix (ids reach agents truncated), it must be a live session the caller can see AND carry the same owner, and **anything unresolvable is DROPPED, never a 400** — a cosmetic field must not be able to fail a worker spawn. It rides `toState()` into `session_created`, so there is no new SSE event. ⚠️ Rendering is an ADDITIONAL LAYER on the existing SVG pass (`_appendLineageConnectionLines` called at the tail of `_updateConnectionLinesImmediate()`, exactly like ultracode), sharing one batched read→write reflow and the `tab:<id>` rect cache; geometry is pure in `computeLineagePath()` (constants.js). ⚠️ **ONE shape, and the second one was the bug**: every pair (flat strip or wrapped) gets a U-bridge hanging below the strip, anchored on both tabs' BOTTOM edges. A wrapped strip used to get a parent-bottom → child-TOP bezier with a ~14px row gap to bend in, which drew a flat line hidden in the gap with siblings overprinting. ⚠️ The dip is a **mis-tuned-in-both-directions corridor** (44px cap = straight thread at strip-wide spans, #285; 104px cap + full row offset = ~106px over-bow into the terminal, 2026-08-15): it now hangs from the **STRIP's bottom edge** (fallback: lower tab bottom), capped at 64px, with NO per-row offsets stacked on top — the strip-bottom baseline is also what keeps a row-1 pair's arc from drawing through row 2's tab labels. ⚠️ **Colors are keyed on the SPAWNING tab, not per child**: every arc leaving one tab is the same color however many workers it spawns, so the strip reads as "these five came from w1, those two came from w2" — per-child coloring gave one tab's own children a different color each, which is the distinction the colors exist to make. A child that spawns in turn is a parent in its own right and gets its own color for the arcs below it, so a chain changes color at each generation while each generation's fan-out stays uniform. Assignment cycles `CodemanLineage.COLORS` in first-seen order per parent id (first entry empty = the skin-tuned `--session-blue`, so the first spawning tab keeps it; the rest vivid fixed hexes), memoized rather than derived from draw index (the SVG is wiped and rebuilt constantly, so an index-based color would flicker), and set inline as `--lineage-color` so styles.css keeps owning opacity/glow/dash. `test/session-lineage-lines.test.ts` drives the real `_appendLineageConnectionLines()` and asserts the painted property, since testing the color function alone would pass just as happily with the child id passed back in. ⚠️ **Desktop only**: the overlay is `z-index: 999` and the desktop header is 100 (arcs paint over it, which is what lets them touch tab bottoms), but under 1024px mobile.css makes the header `fixed; z-index: 1200` and would bury them. ⚠️ Paths carry `data-agent-id="lineage:<childId>"` because that is what `_applyLineEntrances()` queries — that one attribute is what gives them the entrance animation and its negative-`animation-delay` resume across `svg.innerHTML=''`. ⚠️ `.session-tabs` is `overflow-x: auto`, so a scrolled-out tab still HAS a rect (over the logo); edges with an endpoint outside the strip are skipped, and a passive `scroll` listener re-anchors the rest.