fix(web Wave 8 W8-8): documents-table polling stale enum strings

[earayu]

Summary

Replace NON_TERMINAL_INDEX_STATUSES Set with the live four-value enum members so document polling actually identifies in-progress index work instead of silently never matching.

Bug

web/src/app/workspace/collections/[collectionId]/documents/documents-table.tsx declared the Set as `(PENDING, CREATING, DELETING, DELETION_IN_PROGRESS)` — three of those four literals were retired when the backend simplified the per-modality index enum to `(PENDING, RUNNING, ACTIVE, FAILED)`. The Set is typed `Set` so tsc never flagged the drift, but `hasNonTerminalDocumentState` would only ever match `'PENDING'` in practice; documents transitioning through the new `'RUNNING'` state were treated as terminal, so the table fell out of fast-poll mode while indexing was still active.

W8-8 sediment from PR #1766 (task #15) findings: type-drift fixed in #1766 is type-safe but did not catch behavior-drift hidden behind `Set` / `Array` literals. Architect msg=ec02b580 authorised this short-term follow-up at own cadence.

§K.12 invariant cross-check

Largely n/a (frontend behavioral fix). Direct hit:

• fix: socket reconnect bug #12 (grep-zero LightRAG) — rg -i lightrag web/src/ returns zero hits both before and after ✅.

4-pattern pre-check matrix

• Pattern 1 v1 (legacy enum literals in this file): `rg "CREATING|DELETION_IN_PROGRESS" documents-table.tsx` returns zero. The remaining `'DELETING'` literal in the other Set (`NON_TERMINAL_DOCUMENT_STATUSES`, line 67) belongs to the separate eight-value `Document.status` enum (`UPLOADED | EXPIRED | PENDING | RUNNING | COMPLETE | FAILED | DELETING | DELETED`), which still includes `DELETING` — leave intact.
• Pattern 1 v2 (consumers of the Set): only one call site, `hasNonTerminalDocumentState`, which polls based on Set membership; no other code reads the Set's contents directly.
• Pattern 2 (response-shape change list): n/a, this PR does not touch any API surface or schema.
• Pattern 3 (additive helpers): n/a, value-set narrowing only.

simple-stable directive 4-guardrail

• feat/frontend #1 不无限扩范围 — single-file two-string Set sweep, ~5 LOC diff. Did not extend to refactor the polling logic or re-derive the Set from the OpenAPI enum (future cleanup, not in scope for the immediate behavior fix).
• feat: auth bearer token support #2 尽快上线 — small targeted fix, ~30 min after task fix: poetry dependencies #15 merge.
• feat: api test #3 简单稳定 — the Set now matches the live enum verbatim (`PENDING`, `RUNNING`); no fragile string-to-string mappings introduced.
• fix: upload token #4 私有化部署免维护 — fix is invisible to operators; restores intended polling behaviour.

Test plan

• yarn tsc --noEmit shows the same 5 pre-existing errors as on main; no new errors introduced.
• Static read: `hasNonTerminalDocumentState` Set membership now returns true for `'PENDING'` and `'RUNNING'` index states (the actual non-terminal states).
• Manual smoke (out of session env): create a fresh collection, upload a document, observe that `documents-table` stays in fast-poll while `vector_index_status === 'RUNNING'` instead of falling back to slow-poll.

🤖 Generated with Claude Code

[earayu]

🟢 LGTM ✅ (huangheng pass-1) — verdict = ready to merge

1 file / +1 / -3 — 严格 W8-8 scope，behavior bug fix 干净（Set 从 stale 4-string (PENDING, CREATING, DELETING, DELETION_IN_PROGRESS) 改 live 2-string (PENDING, RUNNING)），polling 在 RUNNING 恢复 fast-poll。

Pattern 1 v1 验证 ✅

cuiwenbo 显式 paste 了 NON_TERMINAL_DOCUMENT_STATUSES (line 67, 8-value Document.status enum 含 DELETING) 与本 PR NON_TERMINAL_INDEX_STATUSES (4-value DocumentIndexStatus enum) 区分清楚 — DELETING 留在 _DOCUMENT_STATUSES 是正确，没误改。这种"两个看起来相似的 Set 区别"的精细辨析是行家级 review 防御。👍

simple-stable 4-guardrail

• #1 不无限扩范围 ✅ 单文件 2-string sweep，不重构 polling 不 derive Set 自 OpenAPI enum (future cleanup 留 W8-9 / W8-10)
• #2 尽快上线 ✅ ~5 LOC after task #15 merge
• #3 简单稳定 ✅ Set 与 live enum verbatim 一致
• #4 私有化免维护 ✅ operator-invisible, 恢复 intended 行为

测试 sediment

manual smoke 显式 defer "out of session env" — 可接受 (cuiwenbo 没本地 backend，task #11 narrative e2e 也 cover indexing flow 一部分；本 fix 是 client-side pure-compute 行为)。如未来需 e2e verify，sediment 进 W8-9 ("frontend behavioral test coverage" candidate)。

@符炫炜 LGTM，可 merge。
@cuiwenbo task #15 type drift + W8-8 behavior drift 双重 sweep + Pattern 1 v1 邻居 Set 辨析精细 — frontend 高质量 follow-up 模板。👍