feat(leftover): persist leftover-map explained share (ADR 0232)

[seonghobae]

Summary

Period leftover pair rows now name leftover-map explained share e = R̂² / R² of raw residual after two-axis Gabriel reconstruction R̂ = ξ_{1:2} · ζ_{1:2} (ADR 0232 / migration 0232). Closest and farthest leftover pairs sit above the member list with R̂²/R² next to leftover-map distance d; click opens that post.

This is not closed historical PR #539. That reconstruction used a centered formula e = R̂_c² / R̃² under ADR 0185. Current main already persists raw-residual cross share x = 2 R̂ U / R² (ADR 0185) and signed reconstruction R̂ (ADR 0201). This increment completes the cell identity e + s + x = 1 by persisting e. Unexplained leftover share s = U² / R² is not persisted.

Buyer next action

Leftover map explains {share} of raw residual after IRT main effects. Open this post to read {criterion}. A missing or non-finite share omits the badge and keeps the existing cross-share / reconstruction / unexplained fallback. A finite share greater than 1 is stored and shown, never clamped: truncated two-axis reconstruction of a higher-rank cell can make |R̂| > |R|. Do not invent a leftover score. Do not invent a theta.

Evidence

• uv run leftover pair tests: 23 passed (tests/test_leftover_pairs.py)
• Migration replay window covers 0232 (add column if not exists, no unit/nonnegative CHECK)
• Frontend: leftoverMapExplainedShare + LeftoverPairList + i18n 81 passed; App leftover cases 2 passed
• Nullable column; unexplained share still absent
• Grounded in Gabriel (1971) and Jeon et al. (2021, eq. 3)

Does not mix into #680 / #714 / #643 stacks. Independent review required; seonghobae will not self-approve.

---

[coderabbitai]

Important

Review skipped

Auto reviews are disabled on base/target branches other than the default branch.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 9d44d4e8-1400-4b38-9c45-e70435cb17ee

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[seonghobae]

Independent review requested. seonghobae will not self-approve. Leftover-map explained share e = R̂² / R² of raw residual (ADR 0232) is the next buyer increment on current main; unexplained share s stays omitted.

[seonghobae]

Rust boundary evidence:

• This PR is stacked on feat(dashboard): quantify cases and preserve project journeys #640 at exact parent ebfe60afa53d0ceff8c8e30392c5c8228ed4a070.
• fast-mlsirm PR #1457 owns explained_share arithmetic in Rust at immutable commit 54bcdf0b1d8a8e98d2265e05e3c03bd42e8b57c2; LineageWeave pins that exact commit.
• LineageWeave only projects result.explained_share; no local SVD or share formula remains.
• Rust focused interaction-map tests: 9 passed. Upstream Python/Rust/package hosted checks are successful; protected delivery still awaits its remaining independent gates.

[seonghobae]

Exact dependency refresh: concurrent upstream work unified the result with the versioned interaction-map envelope. This PR now pins current #1457 head 5c7dc9ead1feddcaff0d6c9032fcace4c7028f7c, which contains the earlier Rust explained-share commit and adds envelope binding, validation, projection, and parity proof. The older 54bcdf0b… evidence remains an ancestor, not the current pin.