fix(loki): spec-contradiction is non-fatal by default (never-fail-a-stage)

The final and most robust layer: a detected spec-contradiction no longer
terminal-fails the run before iteration 1. It is recorded as a high-severity
finding and the build PROCEEDS. This is safe: the completion gate still refuses a
"green" done while an unresolved contradiction stands and it is surfaced in
proof-of-done, so nothing fakes success -- this only stops a false-positive from
KILLING a valid build at 0 iterations. Observed: the LLM grill classifier
over-fires "contradiction" on ordinary ambiguities in real PRDs
(saas-dashboard, markdown-notes killed at 0 iters while landing-page and
url-shortener built cleanly from equivalent specs). Combined with the no-retry
exit-20 terminal, a flaky/mislabeled verdict was a hard build failure.

Default flipped: LOKI_SPEC_CONTRADICTION_FASTFAIL now defaults 0 (proceed);
set =1 to restore the old hard terminal. Companion to the classifier layering
(b5fa4ed/e4d9f4e8/80b02d6c/a3be6479). Feature-branch only.

Claude-Session: https://claude.ai/code/session_01VyBdR1hf2uUTwd84f9amTa

Author: asklokesh

autonomy/run.sh

@@ -16948,7 +16948,16 @@ except Exception:
         #       specific count, NOT the broader high-unresolved which includes
         #       auto-ackable non-contradictions).
         # Opt-out: LOKI_SPEC_CONTRADICTION_FASTFAIL=0.
-        if [ "${LOKI_SPEC_CONTRADICTION_FASTFAIL:-1}" = "1" ] \
+        # NEVER-FAIL-A-STAGE default (founder policy): a spec-contradiction is now
+        # NON-FATAL by default -- it is recorded as a high-severity finding and the
+        # build PROCEEDS (the completion gate still refuses a "green" done while an
+        # unresolved contradiction stands, and it is surfaced in proof-of-done, so
+        # this never fakes success; it only stops a false-positive from terminating
+        # a valid build before iteration 1). The grill classifier is an LLM and
+        # over-fires; combined with the no-retry terminal that produced valid
+        # specs killed at 0 iterations. Opt INTO the old hard terminal-fail with
+        # LOKI_SPEC_CONTRADICTION_FASTFAIL=1 (default is now 0).
+        if [ "${LOKI_SPEC_CONTRADICTION_FASTFAIL:-0}" = "1" ] \
            && [ ! -t 0 ] \
            && [ "${LOKI_ASSUMPTIONS_REQUIRE_CONFIRM:-0}" != "1" ] \
            && type spec_ledger_contradiction_unresolved_count &>/dev/null; then