Add the startup self-test and the loopd selftest command

Implemented-By: OpenCode session (model recorded in docs/implementer-log.md)

docs/implementer-log.md

@@ -26,6 +26,7 @@ reviewer adds findings under "Reviews" once per milestone.
 | M2a/11-llama-gate-retry | 2026-09-18 | done | 3 | fail | none | Prerequisite `chat` (M2a/09) now exists, so the task was possible. Implemented `SlotGate` in gate.rs: per-slot holder + a `VecDeque` of arrival tickets, `notify_all`, a woken waiter takes the slot only if free and its ticket is at the front (and claims it by setting holder), `Drop` frees and wakes; mutex/condvar poison recovered via `unwrap_or_else(...into_inner)`, no `unwrap`. Implemented `chat_with_retry` + `is_retryable` (all nine variants, a new one is a compile error) + `backoff_ms` in retry.rs: base is `schedule[retry-1]` or last or 0, jitter clamped and computed in `i128` so `u64::MAX` never overflows, jitter from sub-second nanos. `chat` acquires the gate for `req.slot` and maps `GateFull`->`InferError::Busy`; `Client` gained a `gate` field. First gate failed on three clippy lints (derivable `Default`, `or_insert_with`->`or_default`), fixed. One logic bug caught by `waiters_are_served_in_order`: `take_if_front` claimed the ticket but not `holder`, letting two permits overlap — set holder on claim. All 79 loopd tests pass; retry 13/13 over ten runs; `make gate` prints `gate: ok`. | ? |
 | M2a/09-llama-chat | 2026-09-18 | done | 1 | pass | none | Wrote crates/loopd/src/llama/chat.rs (`chat`, with the head wait in a separate `wait_for_head`) and registered `pub mod chat;`. `chat` builds the body (build error -> Protocol), opens and POSTs, then `wait_for_head` loops `read_head` at `poll_ms`: a Timeout is classified Idle/Busy/Unavailable by `received_any` then a `slots()` poll, emits `Waiting { slot_busy }` on every poll, keeps a per-state `since` that resets on state change, and returns `WaitTimeout`/`LoadTimeout`/`Stalled` at the right limits; 200 streams via `Events`+`Assembler` mapping `Timeout->Stalled`, `Truncated->StreamClosedEarly`, else `Protocol`, then `finish(false)`; non-200 returns `Http { status, error_text }`. All 13 chat tests pass five runs in a row. Table-to-test map: state (table 1) Busy -> a_busy_slot_is_waited_out / a_slot_that_stays_busy_is_a_wait_timeout, Idle-not-processing -> only_the_requests_own_slot_counts_as_busy, Unavailable -> an_unavailable_server_is_a_load_timeout, Idle-received_any -> a_slow_but_steady_stream_is_not_a_stall (turn1 head is 738 B, pieces are 3140/8=392 B, so the head-wait times out with a partial head); thresholds (table 2) -> a_slot_that_stays_busy_is_a_wait_timeout / an_unavailable_server_is_a_load_timeout / only_the_requests_own_slot_counts_as_busy; stream (table 3) Data/Done/None -> the recorded completion and trickle tests, Timeout -> silence_in_mid_stream_is_a_stall, Truncated -> a_stream_that_is_cut_is_closed_early_wherever_the_cut_falls, other -> garbage_in_the_stream_is_a_protocol_error; clock-restart -> the_wait_clocks_restart_when_the_state_changes. One path fix: info and request live under crate::llama, not crate::, so the imports use crate::llama::{info::..., request::...}. | ? |
 | M2a/10-llama-cap | 2026-09-18 | done | 1 | pass | none | Added `Client::end_reasoning` to info.rs: POSTs `{"id","action":"reasoning_end","model"}` to `/v1/chat/completions/control` via `call`, reads `success` as a bool from the server's JSON (ignoring `message`), non-200 stays an Err through `call`, a missing/non-bool `success` is Protocol. Threaded the cap into `chat` step 4: after passing a chunk's events on, when `assembler.in_reasoning()`, a local `cap_at: Option<u64>` holds where the cap fired (None while it has not fired); on `tokens >= thinking_cap` it calls `end_reasoning(assembler.id())` once, remembers `tokens` and emits `ThinkingCapped` on `Ok(true)`, returns `ThinkingOverrun` on `Ok(false)`/`Err`, and after firing returns `ThinkingOverrun` once `tokens >= at + thinking_overrun`; `finish(cap_at.is_some())`. The `the_allowance_is_exact` test passes with `>=` in both rows (63 is not `20+44`, and is `>= 20+43`). One guard: a reasoning chunk with no id at cap time is Protocol rather than a panic. 6 cap tests + 13 chat tests pass; `make gate` prints `gate: ok`. | ? |
+| M2a/12-selftest | 2026-09-18 | done | 1 | pass | none | Wrote crates/loopd/src/selftest.rs (SelfTestError with Display/std::error::Error/From<InferError>, and `run` doing the three checks in order) and registered `pub mod selftest;` in lib.rs; rewrote main.rs into `loopd selftest --config <path>`. Check 1 calls props() and compares chat-template sha256, then n_ctx, then total_slots, a sha256 error being Hash so a wrong server is sent no prompt; check 2 posts one read_file tool with chat_with_retry and requires finish_reason ToolCalls, a first call named read_file whose arguments parse as JSON carrying a string path, wrapping an InferError as Infer; check 3 runs turn 1 then an extension of it and maps a cache Loss to CacheMiss. The copied test's cache_outcome/CacheOutcome live at crate::llama::info, so the import follows that. main.rs parses args as &[&str] via a two-step String->&str collect; unknown/missing args are exit 2 and a config load failure is `loopd: <error>` exit 1. Real server via inferproxy against straylight: minimal.toml gave three step lines and `selftest: ok` exit 0; setting slots=3 gave `selftest: FAILED: slot count: expected 3, got 2` exit 1. | ? |
 
 
 ## Reviews