Drop the generated search index; derive it from the source instead

The index file was 12KB of which ~96% was a byte-for-byte copy of
database/goodman-1.6.jsonl. Its only original content was three derived
fields: `name` (literally id.replace('-','_')), `status` (a two-line
computation over proof_checked), and `identifiers` (a regex over the
statement). It was a cache for work that costs microseconds, and it
created a real hazard: nothing checked that it matched its source, so
editing a statement and forgetting to regenerate would leave
search_database.py serving a premise whose text no longer matched the
generated .lean file.

- search_database.py now reads database/goodman-1.6.jsonl directly via a
  new load_database(), deriving name/identifiers/status on the fly and
  importing those functions from build_database.py so there is one
  definition of each rather than two that can drift.
- build_database.py drops --out-index and index generation, and its
  proof/status derivation is factored into resolve_proof() shared with
  retrieval.
- database/goodman-1.6.index.jsonl deleted.

Also fixes a retrieval bug the removal surfaced: the tokenizer only
matched ASCII identifiers, so a goal that is pure algebra
("a * (b + c) = a * b + a * c") tokenized to nothing and retrieved
nothing at all -- it now keeps type and operator symbols, and drops
single-letter variable names, which say nothing when matched. That goal
now correctly finds Proposition 1.6.1, and the identifier-rich goals
still rank their exact premise first by a wide margin (9.3 vs 4.4).

Tests restructured accordingly: the proof gate is now pinned directly on
resolve_proof in both directions, plus new coverage for load_database
deriving status from proof_checked and for the symbol tokenization.
49 tests, 48 green (the one failure remains the pre-existing unrelated
lean_agent import error in test_dataset.py).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017vbLFFJiHSZqGZHEkjvG5x

database/goodman-1.6.index.jsonl

@@ -1,21 +0,0 @@
-{"name": "goodman_1_6_1", "id": "goodman-1-6-1", "source_label": "Proposition 1.6.1", "kind": "proposition", "status": "proof_pending", "proof": "intro a b c\nrefine ⟨by ring, by ring, by ring, by ring, by ring, by ring, by ring, by ring, ?_⟩\nintro x y h\nexact ⟨fun hx => h (by simp [hx]), fun hy => h (by simp [hy])⟩", "statement": "∀ (a b c : ℤ), (a + b = b + a) ∧ (a + (b + c) = (a + b) + c) ∧ (0 + a = a) ∧ (a + (-a) = 0) ∧ (a * b = b * a) ∧ (a * (b * c) = (a * b) * c) ∧ (1 * a = a) ∧ (a * (b + c) = a * b + a * c) ∧ (∀ (x y : ℤ), x * y ≠ 0 → x ≠ 0 ∧ y ≠ 0)", "natural_language": "Addition and multiplication on the integers are commutative and associative, 0 and 1 are their respective identities, the distributive law holds, and a product of integers is nonzero iff both factors are nonzero.", "identifiers": [], "requires": ["Int.add_comm", "Int.add_assoc", "Int.zero_add", "Int.add_left_neg", "Int.mul_comm", "Int.mul_assoc", "Int.one_mul", "Int.mul_add", "Int.mul_ne_zero"]}
-{"name": "goodman_1_6_4", "id": "goodman-1-6-4", "source_label": "Proposition 1.6.4", "kind": "proposition", "status": "proof_pending", "proof": "intro n hn\nobtain ⟨p, hp, hpd⟩ := Nat.exists_prime_and_dvd (show n ≠ 1 by omega)\nexact ⟨p, hp, hpd⟩", "statement": "∀ (n : ℕ), n > 1 → ∃ (p : ℕ) (h : Nat.Prime p), p ∣ n", "natural_language": "Any natural number greater than 1 can be written as a product of prime numbers.", "identifiers": ["Nat.Prime"], "requires": ["Nat.exists_prime_factor"]}
-{"name": "goodman_1_6_6", "id": "goodman-1-6-6", "source_label": "Theorem 1.6.6", "kind": "theorem", "status": "asserted", "proof": null, "statement": "∃ (p : ℕ → ℕ), ∀ (n : ℕ), Nat.Prime (p n) ∧ ∀ (i j : ℕ), i ≠ j → p i ≠ p j", "natural_language": "There are infinitely many prime numbers.", "identifiers": ["Nat.Prime"], "requires": ["Nat.infinite_primes"]}
-{"name": "goodman_1_6_7", "id": "goodman-1-6-7", "source_label": "Proposition 1.6.7", "kind": "proposition", "status": "asserted", "proof": null, "statement": "∀ (a d : ℤ), d ≥ 1 → ∃! qr : ℤ × ℤ, a = qr.1 * d + qr.2 ∧ 0 ≤ qr.2 ∧ qr.2 < d", "natural_language": "Given integers a and d with d ≥ 1, there exist unique integers q and r such that a = qd + r and 0 ≤ r < d.", "identifiers": ["qr"], "requires": ["Int.division_theorem"]}
-{"name": "goodman_1_6_9", "id": "goodman-1-6-9", "source_label": "Proposition 1.6.9", "kind": "proposition", "status": "asserted", "proof": null, "statement": "∀ (m n : ℤ), let I := {v : ℤ | ∃ a b : ℤ, v = a * m + b * n}; (∀ x ∈ I, ∀ y ∈ I, x + y ∈ I) ∧ (∀ x ∈ I, -x ∈ I) ∧ (∀ x : ℤ, ∀ z ∈ I, x * z ∈ I) ∧ (∀ b : ℤ, b ∣ m ∧ b ∣ n → ∀ z ∈ I, b ∣ z)", "natural_language": "I(m,n) = {am+bn} is closed under addition and negation, absorbs multiplication by any integer, and any common divisor of m and n divides every element of I(m,n).", "identifiers": [], "requires": []}
-{"name": "goodman_1_6_10", "id": "goodman-1-6-10", "source_label": "Lemma 1.6.10", "kind": "lemma", "status": "asserted", "proof": null, "statement": "∀ (m n d : ℤ), d ∣ m ∧ d ∣ n ∧ d ∈ {v : ℤ | ∃ a b : ℤ, v = a * m + b * n} → ∀ (x : ℤ), x ∣ m ∧ x ∣ n → x ∣ d", "natural_language": "If a natural number d is a common divisor of m and n and an element of I(m, n), then d is the greatest common divisor of m and n.", "identifiers": [], "requires": ["Int.gcd_is_greatest_common_divisor"]}
-{"name": "goodman_1_6_11", "id": "goodman-1-6-11", "source_label": "Proposition 1.6.11", "kind": "proposition", "status": "asserted", "proof": null, "statement": "∀ (m n : ℤ), m ≠ 0 ∧ n ≠ 0 → let d := Nat.gcd (Int.natAbs m) (Int.natAbs n); (d : ℤ) = Int.gcd m n ∧ (d : ℤ) ∈ {v : ℤ | ∃ a b : ℤ, v = a * m + b * n}", "natural_language": "The natural number d, which is the greatest common divisor of the absolute values of m and n, is also the greatest common divisor of m and n, and d is an element of I(m, n).", "identifiers": ["Nat.gcd", "Int.natAbs", "Int.gcd"], "requires": ["Int.gcd_nat_abs", "Int.gcd_linear_combination"]}
-{"name": "goodman_1_6_13", "id": "goodman-1-6-13", "source_label": "Corollary 1.6.13", "kind": "corollary", "status": "asserted", "proof": null, "statement": "∀ (m n : ℤ), m ≠ 0 → n ≠ 0 → let I := {v : ℤ | ∃ a b : ℤ, v = a * m + b * n}; let d := Int.gcd m n; IsLeast {x : ℤ | 0 < x ∧ x ∈ I} (d : ℤ) ∧ I = {v : ℤ | ∃ k : ℤ, v = k * d}", "natural_language": "gcd(m,n) is the least positive element of I(m,n), and I(m,n) is exactly the set of integer multiples of gcd(m,n).", "identifiers": ["Int.gcd", "IsLeast"], "requires": ["IsLeast", "Int.gcd"]}
-{"name": "goodman_1_6_15", "id": "goodman-1-6-15", "source_label": "Corollary 1.6.15", "kind": "corollary", "status": "proof_pending", "proof": "intro m n _\nrw [Int.gcd_eq_one_iff_coprime]\nconstructor\n· intro h\n  obtain ⟨u, v, huv⟩ := h\n  exact ⟨u, v, huv⟩\n· intro h\n  obtain ⟨s, t, hst⟩ := h\n  exact ⟨s, t, hst⟩", "statement": "∀ (m n : ℤ), m ≠ 0 ∧ n ≠ 0 → Int.gcd m n = 1 ↔ ∃ (s t : ℤ), s * m + t * n = 1", "natural_language": "Two nonzero integers m and n are relatively prime if and only if there exist integers s and t such that sm + tn = 1.", "identifiers": ["Int.gcd"], "requires": ["Int.coprime_iff_gcd_eq_one"]}
-{"name": "goodman_1_6_17", "id": "goodman-1-6-17", "source_label": "Corollary 1.6.17", "kind": "corollary", "status": "proof_pending", "proof": "intro a b x h\nexact IsCoprime.mul_dvd (Nat.isCoprime_iff_coprime.mpr h.1) h.2.1 h.2.2", "statement": "∀ (a b : ℕ) (x : ℤ), Nat.Coprime a b ∧ (a:ℤ) ∣ x ∧ (b:ℤ) ∣ x → (a:ℤ) * b ∣ x", "natural_language": "If a and b are relatively prime natural numbers and both divide an integer x, then their product ab also divides x.", "identifiers": ["Nat.Coprime"], "requires": ["Nat.coprime_mul_dvd"]}
-{"name": "goodman_1_6_18", "id": "goodman-1-6-18", "source_label": "Proposition 1.6.18", "kind": "proposition", "status": "asserted", "proof": null, "statement": "∀ (p : ℕ) (a : ℤ), Nat.Prime p ∧ a ≠ 0 → (p:ℤ) ∣ a ∨ IsCoprime (p:ℤ) a", "natural_language": "If p is a prime number and a is any nonzero integer, then either p divides a or p and a are relatively prime.", "identifiers": ["Nat.Prime", "IsCoprime"], "requires": ["Int.prime_or_coprime"]}
-{"name": "goodman_1_6_19", "id": "goodman-1-6-19", "source_label": "Proposition 1.6.19", "kind": "proposition", "status": "proof_pending", "proof": "intro p a b h hdvd\nexact Int.Prime.dvd_mul' h.1 hdvd", "statement": "∀ (p : ℕ) (a b : ℤ), Nat.Prime p ∧ a ≠ 0 ∧ b ≠ 0 → (p:ℤ) ∣ a * b → (p:ℤ) ∣ a ∨ (p:ℤ) ∣ b", "natural_language": "If p is a prime number and a and b are nonzero integers, and p divides the product ab, then p divides a or p divides b.", "identifiers": ["Nat.Prime"], "requires": ["Int.prime_dvd_mul"]}
-{"name": "goodman_1_6_20", "id": "goodman-1-6-20", "source_label": "Corollary 1.6.20", "kind": "corollary", "status": "proof_pending", "proof": "intro p as hp _ h\nobtain ⟨a, ha, hpa⟩ := (Nat.Prime.prime_int hp).dvd_prod_iff.mp h\nexact ⟨a, ha, hpa⟩", "statement": "∀ (p : ℕ) (as : List ℤ), Nat.Prime p → (∀ (a : ℤ), a ∈ as → a ≠ 0) → (p:ℤ) ∣ List.prod as → ∃ (a : ℤ), a ∈ as ∧ (p:ℤ) ∣ a", "natural_language": "If a prime number p divides a product of nonzero integers, then p divides one of the factors.", "identifiers": ["as", "List", "Nat.Prime", "List.prod"], "requires": ["Int.prime_dvd_prod"]}
-{"name": "goodman_1_6_21", "id": "goodman-1-6-21", "source_label": "Theorem 1.6.21", "kind": "theorem", "status": "asserted", "proof": null, "statement": "∀ (n : ℕ), n > 1 → ∃! (ps : List ℕ), (∀ (p : ℕ), p ∈ ps → Nat.Prime p) ∧ n = List.prod ps", "natural_language": "The prime factorization of a natural number is unique.", "identifiers": ["ps", "List", "Nat.Prime", "List.prod"], "requires": ["Nat.unique_prime_factorization"]}
-{"name": "goodman_1_6_23", "id": "goodman-1-6-23", "source_label": "Lemma 1.6.23", "kind": "lemma", "status": "asserted", "proof": null, "statement": "∀ (n : ℕ) (a : Fin n → ℤ), 2 ≤ n → (∀ i, a i ≠ 0) → ∃ (d : ℕ) (Q : Matrix (Fin n) (Fin n) ℤ), IsUnit Q.det ∧ ∀ j : Fin n, Matrix.vecMul a Q j = if j.val = 0 then (d : ℤ) else 0", "natural_language": "Given n >= 2 nonzero integers a_1..a_n, there is a natural number d and a unimodular (det a unit, i.e. det = +-1) integer n-by-n matrix Q such that the row vector a times Q equals (d, 0, ..., 0).", "identifiers": ["Fin", "Matrix", "IsUnit", "Q.det", "Matrix.vecMul", "j.val"], "requires": ["Matrix.vecMul", "Matrix.det", "IsUnit"]}
-{"name": "goodman_1_6_24", "id": "goodman-1-6-24", "source_label": "Proposition 1.6.24", "kind": "proposition", "status": "asserted", "proof": null, "statement": "∀ (as : List ℤ), as.length ≥ 2 → (∀ (a : ℤ), a ∈ as → a ≠ 0) → ∃ (d : ℕ) (cs : List ℤ), IsGCDOfList d as ∧ (d:ℤ) = List.sum (List.zipWith (· * ·) cs as)", "natural_language": "The greatest common divisor of a list of at least two nonzero integers exists and is an integer linear combination of the integers in the list.", "identifiers": ["as", "List", "as.length", "cs", "IsGCDOfList", "List.sum", "List.zipWith"], "requires": ["GCD.gcd_exists", "GCD.gcd_linear_combination"]}
-{"name": "goodman_1_6_26", "id": "goodman-1-6-26", "source_label": "Lemma 1.6.26", "kind": "lemma", "status": "asserted", "proof": null, "statement": "∀ (as : List ℤ) (z : ℤ), as.length ≥ 2 → (∀ (i j : ℕ), i ≠ j → i < as.length → j < as.length → IsCoprime (as[i]) (as[j])) → (∀ (a : ℤ), a ∈ as → a ≠ 0) → (∀ (a : ℤ), a ∈ as → a ∣ z) → List.prod as ∣ z", "natural_language": "If a list of integers is pairwise relatively prime and each integer in the list divides an integer z, then the product of the integers in the list also divides z.", "identifiers": ["as", "List", "as.length", "IsCoprime", "List.prod"], "requires": ["Int.pairwise_coprime_mul_dvd"]}
-{"name": "goodman_1_6_2_a", "id": "goodman-1-6-2-a", "source_label": "Proposition 1.6.2", "kind": "proposition", "status": "proof_pending", "proof": "intro u v h\nexact Int.mul_eq_one_iff_eq_one_or_neg_one.mp h", "statement": "∀ (u v : ℤ), u * v = 1 → (u = 1 ∧ v = 1) ∨ (u = -1 ∧ v = -1)", "natural_language": "If two integers multiply to 1, both are 1 or both are -1.", "identifiers": [], "requires": ["Int.eq_one_or_self_of_prime"]}
-{"name": "goodman_1_6_2_b", "id": "goodman-1-6-2-b", "source_label": "Proposition 1.6.2", "kind": "proposition", "status": "proof_pending", "proof": "intro a b h\nexact Int.associated_iff.mp (associated_of_dvd_dvd h.1 h.2)", "statement": "∀ (a b : ℤ), a ∣ b ∧ b ∣ a → a = b ∨ a = -b", "natural_language": "If two integers divide each other, they are equal or negatives of each other.", "identifiers": [], "requires": ["Int.dvd_antisymm"]}
-{"name": "goodman_1_6_2_c", "id": "goodman-1-6-2-c", "source_label": "Proposition 1.6.2", "kind": "proposition", "status": "proof_pending", "proof": "intro a b c h\nexact dvd_trans h.1 h.2", "statement": "∀ (a b c : ℤ), a ∣ b ∧ b ∣ c → a ∣ c", "natural_language": "Divisibility of integers is transitive.", "identifiers": [], "requires": ["Int.dvd_trans"]}
-{"name": "goodman_1_6_2_d", "id": "goodman-1-6-2-d", "source_label": "Proposition 1.6.2", "kind": "proposition", "status": "proof_pending", "proof": "intro a b c s t h\nexact dvd_add (h.1.mul_left s) (h.2.mul_left t)", "statement": "∀ (a b c s t : ℤ), a ∣ b ∧ a ∣ c → a ∣ (s * b + t * c)", "natural_language": "If an integer divides two others, it divides any integer linear combination of them.", "identifiers": [], "requires": ["dvd_add", "Dvd.dvd.mul_left"]}