docs: fix Bet365 tier + 3 audit doc gaps (c8594804) — Fixes #265

[Mlaz-code]

What

Closes the four documentation gaps from the Crisp c8594804 diligence audit (engineering verdicts in Mlaz-code/sharp-api-go#885). Each fix was verified against current code, not just the issue text.

#	Gap	Code truth	Fix
1	live-vs-prematch.mdx tier table lists Bet365 = Pro	RequiresTier: "hobby" (sharp-api-go/sportsbooks.go:33-34); api-reference/sportsbooks.mdx already says Hobby	Bet365 → Hobby (all 4 locales)
2	stream.mdx documents channel as a single value only	sse.go:253-271 accepts channel/channels as CSV; >1 valid channel collapses to all; WS does true selective multi-channel	Documented the channels alias + collapse-to-all, with a callout contrasting the WS API (all 4 locales)
3	/odds/best — is_main_line reads like a "main game lines only" filter	is_main_line is per-(event, market_type, selection) cohort, so period/prop mains legitimately carry is_main_line=true; ?market=main is the full-game filter (main.go:7721-7730)	Added a callout spelling out is_main_line vs ?market=main (all 4 locales)
4	event-matching.mdx documents the _bN bucket but gives no cross-bucket grouping recipe	strip_doubleheader_suffix / same_event strip _g{N} and keep _b{N}; bucket deliberately separates doubleheaders (api-adapters/utils/canonical_ids.py:531-559)	Added the _g{N} doubleheader suffix + a two-level grouping recipe (safe same-fixture collapse vs. loose display grouping, with the doubleheader tradeoff stated)

Why the recipe has two levels (item 4)

The issue suggested a single recipe — strip _b{N}/_g{N} and group by {league}_{teams}_{date}. But the _b{N} bucket exists precisely to keep same-day doubleheaders and cross-midnight rematches apart, so blindly stripping it re-merges genuine doubleheaders. The doc now gives both levels and states the tradeoff honestly:

1. Same-fixture collapse (recommended) — strip only _g{N}, keep _b{N} (mirrors the server-side same_event predicate).
2. Loose matchup grouping (display) — also strip _b{N}, group by {league}_{teamA}_{teamB}_{date}, ±1 day; note that this collapses real doubleheaders.

Scope note (i18n)

Item 4 is English-only: the de / es / pt-BR event-matching.mdx pages predate the SHA-3432 _bN documentation entirely (they still show the old nba_celtics_lakers_20260208 date format and have no bucket section), so a grouping recipe has no coherent place to attach there. Items 1–3 are applied across all four locales. Follow-up: backfill the full _bN bucket section into the three translated event-matching.mdx pages.

Verification

• npm run build (full pipeline — next build across all 4 locales, 224 pages) passes; pagefind indexes cleanly.
• All <Callout> tags balanced; new code fences render inside the numbered list.

Fixes #265

Type: docs

🤖 Generated with Claude Code

[Mlaz-code]

@Mlaz-code ⏰ ready-to-merge ping — this PR is clean + mergeable but has sat idle ~3.5 days (opened 2026-06-18 19:35Z, 0 reviews / 0 comments, untouched).

State: mergeable: MERGEABLE, mergeStateStatus: CLEAN, not draft, no pending checks. One click merges it.

On merge: Fixes #265 auto-closes and Vercel redeploys main, so the 4 c8594804-audit doc fixes go live on docs.sharpapi.io:

• Bet365 live tier Pro → Hobby (matches sharp-api-go RequiresTier="hobby")
• SSE channel/channels CSV semantics → collapses >1 valid channel to all (vs WS selective multi-channel)
• is_main_line clarified as per-(event,market_type,selection) cohort vs the ?market=main filter
• _bN cross-bucket grouping recipe (_g{N} doubleheader suffix)

Not live yet: origin/main still shows | Bet365 | Yes | … | Pro | (content/en/concepts/live-vs-prematch.mdx:123).

The de/es/pt-BR _bN i18n backfill is intentionally a separate follow-up (this PR fixes EN only for that section) — not a merge blocker.

_{Automated re-verification ping — crew #934 / Sentinel routine 53.}