fix(mp-8pba): dispatch Swiss standings on engi flags and team sub-bouts

[gitrgoliveira]

Summary

• Swiss standings now dispatch on competition type. SwissStandings was the only standings routine that never branched on engi vs team vs individual: it unconditionally tallied match-level ippons, so engi Swiss (flag-scored) and team Swiss (sub-bout-scored) competitions lost all their tie-break data and fell through to head-to-head, then name order.
• Engi Swiss now ranks by Wins -> accumulated own-side Flags -> head-to-head -> name; team Swiss now accrues IV/IL/IT/PW/PL from SubResults and ranks on the full team chain -> head-to-head -> name. The individual path is unchanged, and head-to-head survives all three.
• Frontend: the Swiss standings table hardcoded the individual W/L/D/PW/PL columns and mapped ipponsGiven->PW, so even a correct backend rendered zeros (engi has no Flags column; team populates pointsWon, not ipponsGiven). It now shows Flags (engi) and IV/IL/IT/PW/PL (team), with a paradigm-aware "Ranked by" caption.

Why

Root cause: unlike computeStandingsFrom (the pool/league core, which branches on comp.Engi and isTeam), SwissStandings had a single ippon-only tally. A team parent match carries no ippons of its own (they live in SubResults) and an engi match carries FlagsA/FlagsB, so both surfaced as all-zero columns and the tie-break collapsed to name order. Swiss exists specifically to separate a large field over a fixed number of rounds, so its tie-break does more work than any other format's.

Decision (recorded per acceptance criteria): duplicate the dispatch inside SwissStandings, NOT route through computeStandingsFrom. The pool core is structurally pool-based (groups matches by poolNameFromMatchID, applies per-pool TB/DH supplementary bouts and manual rank overrides). Swiss matches are keyed by parseSwissMatchRound (Swiss-R{n}-{i}), form one cumulative cross-round group with bye-as-win semantics and a head-to-head tiebreak the pool path lacks. Routing Swiss through the pool core would drop every Swiss match (no pool ID). So the fix mirrors the pool path's dispatch while keeping Swiss's bye + head-to-head logic; the engi branch delegates to engi.go to honor the hard-separation principle.

Engi keying subtlety (caught during browser UAT): Swiss matches persist no per-side UUIDs (SideAID/SideBID/WinnerID are empty in pool-matches.csv), and Swiss already treats names as unique identities. computeEngiSwissStandings therefore keys the roster by name; an engiPlayerKey ("id:") roster would never match the empty-ID matches and would tally nothing.

Files changed

File	What
internal/engine/swiss.go	SwissStandings dispatches: engi -> computeEngiSwissStandings; team -> inline SubResults accrual + teamStandingPoints sort; individual unchanged. Team score summary added.
internal/engine/engi.go	New computeEngiSwissStandings (Wins -> own-side Flags -> head-to-head -> name, keyed by name). Imports domain.
internal/engine/scoring.go	Shared helpers extracted after tri-review: accrueTeamSubResults, teamScoreSummary, individualScoreSummary (single definition of the team accrual + summary formats, used by both the pool core and Swiss).
internal/engine/swiss_test.go	TestSwissStandings_Engi and TestSwissStandings_Team, using representative empty-ID Swiss matches.
web-mobile/js/viewer_standings.jsx	SwissStandingsViewer reuses StandingsTableHead for engi (Flags) and team (IV/IL/IT/PW/PL) columns + paradigm-aware caption.
web-mobile/js/__tests__/swiss_standings_viewer.test.jsx	New guard test for the engi Flags and team IV/PW columns.
docs/user-guide/organisers/naginata.md	Engi tie-break section now covers Swiss (with its head-to-head step) + engi Swiss standings screenshot.
docs/user-guide/organisers/team-tournaments.md	Team tie-break chain now scoped to Swiss too (+ head-to-head/name fallbacks) + team Swiss standings screenshot.
docs/user-guide/organisers/formats.md	Swiss standings step links the kind-specific ranking detail.
docs/screenshots/swiss-standings-{engi,team}.png	New docs screenshots (from this PR's browser verification).

Review

Tri-review (simplify + correctness + security, adversarially verified) ran post-CI: correctness and security lenses clean; the one confirmed simplify finding (team accrual/summary duplicated from computeStandingsFrom) is fixed in 7803bacd by extracting shared helpers, plus a sibling-sweep engiScoreSummary.

Screenshots

Engi Swiss standings (2 rounds) — Bravo (1W, 7 flags) correctly ranks above Alpha (1W, 5 flags) on the flag tie-break; before the fix both showed 0 flags and the tie fell to name order:

Team Swiss standings (2 rounds) — Bara (1W, IV 3) correctly ranks above Aoi (1W, IV 2) on the individual-victory tie-break; before the fix IV/PW rendered as zeros:

Test plan

• make go/test passes (lint + security scan + tests); engine coverage 86.1% (>=85%)
• npm test (JS) passes — 2473 tests; oxlint clean
• New/updated unit tests cover the change, each confirmed red without the fix (Go TestSwissStandings_Engi/_Team; JS swiss_standings_viewer)
• Manual browser verification: created an engi Swiss and a team Swiss competition, scored both over 2 rounds through the admin UI, and confirmed the public standings table renders the Flags / IV columns with the correct tie-break ordering (screenshots above)
• Screenshots added above