feat(math): Clojure hash-map iteration order for the in-conv greedy tie-break (legacy)

[jucor]

The greedy floor (conversation.clj:259-268) sorts the user-vote-counts
hash-map with a STABLE sort by count desc — so equal-count ties follow
Clojure's PersistentHashMap ITERATION ORDER, which is deterministic:
sort by successive 5-bit chunks (low first) of Murmur3 hashLong
(Clojure hasheq for Long keys). Validated against three recorded-blob
oracles (user-vote-counts raw key order: vw front-loaded6 n=18, vw
uniform8 n=30, biodiversity n=98 — all exact).

The PR-E port assumed this order was non-deterministic and substituted
matrix row order; on vw front-loaded6 step 0 that admits pid 14 where
Clojure admits pid 17 (five-way 1-vote tie at the floor boundary),
seeding an in-conv/base-cluster membership divergence that cascades
through every downstream key — the battery's last diverging entry.

Adds polismath/utils/clj_hash.py (hashLong + HAMT key order; int keys
only, with a documented row-order fallback otherwise) and applies it to
the legacy greedy candidate order. Array-map (≤8 entries, insertion
order) cannot affect the pick: ties only matter with ≥16 participants,
which guarantees hash-map. Improved mode unchanged.

commit-id:d5f1f51d

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Stack:

• docs(delphi): overnight pre-cutover audit (s6) — CUTOVER_RUNBOOK + journal #2659
• feat(delphi): zid-sharding for the math poller — one shard = one process #2658
• ci: run postgres integration tests #2637
• feat(delphi): poller-equivalence harness (goal condition 2) — PASSES live on vw + pc-meta-02 #2657
• feat(math): moderation + restart replay parity — mod_update, restart-seam restore, Q13-Q18 #2656
• docs(delphi): R1-parity goal docs, journal (2026-07-18 → 07-24 s5), quirks + divergence ledger #2626
• feat(delphi): Q12 carve-out — pin the cold-tick PCA start to ones in both replay drivers #2655
• feat(math): Q11 — replicate vectorz distance cancellation in legacy kmeans #2654
• feat(math): small-N degenerate parity — run the real math on tiny matrices in clojure-legacy mode #2653
• feat(delphi): Q10 carve-out — pin large-conv cutoffs to certify the deterministic full-PCA path #2652
• feat(delphi): replay loader resolves private datasets under real_data/.local #2651
• feat(math): Clojure hash-map iteration order for the in-conv greedy tie-break (legacy) #2650 ⬅
• feat(math): clojure-legacy blob emission + selection parity — Clojure-exact math_main at step 0 #2649
• feat(delphi): acceptance canonicalization — suppress cross-engine ordering artifacts in certify comparer #2648
• feat(delphi): certify.py battery runner + focuser + fingerprint ledger (Spec A, Phase 0) #2647
• feat(delphi): prodclone extractor — feature-filtered dataset export (Spec B) #2646
• feat(math): un-mirror priority_metric (#2571 resolved) + Q2 prev-tick group-votes #2645
• feat(math): participant-ban leak replication in clojure-legacy mode (Q1) #2644
• feat(delphi): Clojure timing probe (Spec C) #2643
• feat(math): degenerate-tick group-clusterings overwrite + <2-participants edge (legacy mode) #2642
• refactor(math): move impl-flag resolver to polismath/utils/env_flags.py #2641
• feat(delphi): Python math poller service (phase 1) — Clojure math-container replacement #2625
• fix(delphi): Clojure-parity math writers + committing write path in PostgresClient #2624
• feat(math): in-conv greedy floor + persistent carry (PR-E) #2623
• feat(math): Clojure-exact base-cluster lineage + warm start (PR-C) #2622
• feat(math): replay harness H-B — Clojure Mode A driver (dev/replay.clj) + cross-language comparer shim #2621
• feat(math): group-k-smoother in clojure-legacy engine mode (PR-D smoother) #2620
• feat(math): PCA warm start in clojure-legacy engine mode (PR-B) #2640
• feat(math): add POLISMATH_ENGINE_MODE flag + prev-tick warm-start scaffolding (PR-A) #2618
• feat(delphi): replay harness H-A — schedule spec+slicer, Python driver, store, step comparer, CLI #2639
• fix(delphi): cold-start generator copies FULL revote history (no DISTINCT ON dedup) #2638
• fix(math): correct comment-extremity sign in pca_project_cmnts (D1b) #2615
• docs(delphi): add math-algorithm history & routing-regression reference #2613

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⚠️ Part of a stack created by spr. Do not merge manually using the UI - doing so may have unexpected results.

[Copilot]

Pull request overview

This PR restores Clojure-legacy parity for the in-conversation (“in-conv”) greedy-floor tie-break by reproducing Clojure PersistentHashMap iteration order (Murmur3 hashLong + HAMT 5-bit chunk traversal) for integer (and numeric-string) keys, and using that ordering as the stable-sort tie base.

Changes:

• Add polismath.utils.clj_hash implementing Clojure hashLong and HAMT-based key iteration order for int-like keys (with a documented fallback).
• Update legacy-mode greedy-floor candidate ordering in Conversation._get_in_conv_participants to follow Clojure hash-map iteration order on equal vote-count ties.
• Add targeted unit/integration tests that pin known hash/HAMT order and validate the greedy-floor tie outcome for both int and string pid shapes.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
delphi/tests/test_clj_hash_order.py	Adds regression tests for Clojure hash-map key order and legacy greedy-floor tie behavior (int + string pids).
delphi/polismath/utils/clj_hash.py	Implements Murmur3 hashLong and a HAMT-path-based ordering function to emulate Clojure PersistentHashMap iteration order.
delphi/polismath/conversation/conversation.py	Switches legacy greedy-floor tie-breaking to Clojure hash-map order by pre-ordering candidates before stable vote-count sorting.

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