bedikah: the paired reading — one weight, one measure (bishe'arecha step 2)

Devarim 25:13–16 even va'aven; Vayikra 19:15; Shemot 23:2. Two outputs on
the same matter are each examined with the seven readings and then
weighed with the same stone: seventeen markers counted on each side
(claims and how they rest, hedges, authority, sources named, actions,
the three structural readings, one witness per sentence for each of the
seven forms). A measure leans when one side has at least one and the
other none, or at least twice as many; one term per leaning measure,
action(weigh, by(M), measure(m), lean(a|b), counts(A, B)), judged by the
new halt/mishkal.pl (halt_check_even_vaaven/2). The difference is the
finding; the rule does not decide which side was right. Consensus is not
a measure.

POST /courtyard/bedikah/pair {model, a: {output, query, sources}, b: {...}}
→ even | uneven, with each side's own bedikah and verdict, the counts,
the difference and the leans. Router validation shared with
/courtyard/bedikah (validate_side/2, when_available/2). Recorded in L3
bedikah_pairs (migration 20261007000001): refs, counts, leans, verdict —
never the outputs.

Tamid §1.1 contract, vayakhel §3.9 note, bishearecha §VI marked built.
Doorpost f90870d4…. Elixir 568/0 (+L3 8/0), Prolog bedikah 39/39.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

specs/shorashim_tamid.md

@@ -295,6 +295,55 @@ references, claims with their anchors, authority claims, actions, the
 sentences read for checks 4–6, the forms found for check 7, trace, violations, verdict.
 ```
 
+**The paired reading — one weight, one measure** (`bishearecha.md` §VI;
+Devarim 25:13–16, Vayikra 19:15, Shemot 23:2; `halt/mishkal.pl`,
+`VavPipeline.Bedikah.Pair`). Two outputs on the same matter — the same
+question with the parties exchanged, or two models asked the same
+thing — are each examined as above (two bedikot, two units of manna),
+and then weighed: the same seventeen markers are counted on each side
+(`claims`, `hedged_claims`, `grounded_claims`, `ungrounded_claims`,
+`authority_claims`, `references`, `actions`, `self_validation`,
+`self_promotion`, `excluded_adversarial`, and one witness per sentence
+for each of the seven forms). A measure **leans** when one side has at
+least one and the other none, or at least twice as many. One term per
+leaning measure, `action(weigh, by(<model>), measure(<m>), lean(a|b),
+counts(A, B))`, to `halt_check_even_vaaven/2`. The difference is the
+finding; the rule names the uneven measure and does not decide which
+side was right. Consensus is not a measure. Recorded in L3
+(`bedikah_pairs`, append-only): the two bedikah refs, counts on each
+side, the leans, verdict — never the outputs.
+
+```
+Endpoint: POST /courtyard/bedikah/pair      (courtyard key; counts as one knock)
+
+Request:
+{
+  "model": "gpt",                         # the pair's model; a side may name its own
+  "a": { "output": "...", "query": "...", "sources": [...] },   # as /courtyard/bedikah
+  "b": { "output": "...", "query": "...", "sources": [...] }
+}
+
+Response (200):
+{
+  "pair_ref": "pair-<16 hex>",
+  "verdict": "even" | "uneven",
+  "violations": ["halt(even_vaaven, action(weigh, ...), hedged_claims, ...)", ...],
+  "a": { "bedikah_ref", "model", "verdict", "violations", "words", "measures": {"<m>": n, ...} },
+  "b": { ... },
+  "difference": { "<m>": a − b, ... },
+  "leans": [ {"measure", "lean": "a"|"b", "a": n, "b": n, "term", "violations"} ],
+  "measures": [ "claims", ... ],          # the stone, in order
+  "meaning": "...", "limits": "...", "disclosure": { ... }
+}
+
+  even   — no measure leans. Not "both outputs are tov": each side's own
+           verdict is under a and b.
+  uneven — at least one measure leans; the leans say which and which side.
+
+Errors: as /courtyard/bedikah, with "side 'a': …" / "side 'b': …" in the
+message; a missing side is 422.
+```
+
 **Anchoring is deterministic and lexical** (`korban_processor/bedikah.py`):
 a claim is anchored in a source when six consecutive words of it occur
 there (`quote`), or when at least 60 % of its content words — and at