Fleet-wide hetero thinking knob
HETERO_THINKING (project channel .env.solidforge, session channel shell export; off|minimal|low|medium|high|xhigh|max) pins both wrappers' different-family legs. Same-family legs keep inheriting the session's level; hetero legs keep model defaults unless overridden — never hardcoded in shipped profiles.
Requested-level semantics (the adversarial design review's decisive finding): pi silently clamps per model — glm-5.3-flash supports only low/high/max (off/minimal run low, medium→high, xhigh→max); qwen-bailian high→xhigh, max→medium. The sidecar stamps the REQUEST (hetero-leg-start.thinking); the clamp matrix is documented in README and both .env.solidforge.example copies. Wrapper-side fail-fast on invalid values is load-bearing — pi itself silently drops them.
Setting the env also suppresses per-provider MODEL=<id>:<level> suffix tuning (the suffix stays the per-provider tool). pd's wrapper has no sidecar — the knob is unobservable there (documented).
Also fixes a stale pd wiring assertion (pre-dated the 0.2.9 flash bump; the review found pd wiring missing from the gate sweep).