docs(bc-cmrs): move CLAUDE.md's domain rules into path-scoped .claude/rules files

[gitrgoliveira]

Summary

• CLAUDE.md drops from 240 KB to 69 KB. The detailed domain rulings move, unchanged, into seven path-scoped files under .claude/rules/. Claude Code loads each file only when a session reads or edits code in that file's area.
• Measured saving: a fresh headless session's first call fell from 135k to 72k tokens of context. Both runs used the same prompt and the same user settings; the only difference is this CLAUDE.md. Every later call in every session and every subagent starts from the smaller base.
• CLAUDE.md keeps a pointer table naming which file governs which area. It also notes that a Serena call does not load these files. A global guard outside this repo refuses a Serena edit in an area until that agent has read its rule file.
• AGENTS.md and GEMINI.md point to .claude/rules/, since only Claude Code loads those files on its own.
• "Keep the orchestrating session small" now says subagents default to Sonnet, and to pass model: "opus" for implementers and the final review round.

Why

Bead bc-cmrs: CLAUDE.md was about 60k tokens, and every model call of every session and subagent loaded it. The bead suggested docs/agents/ or .claude/rules/. The rules went to .claude/rules/, not docs/, because docs/ is the public MkDocs site and these rules are full of bead ids and internal references. A plain @import would not have helped, because Claude Code loads imports at launch.

Files changed

File	What
CLAUDE.md	Domain sections moved out; pointer table; subagent model line; corrected size note
.claude/rules/draw-and-seeding.md	Tree, seeding, pool creation, tree-aware seeding, pool bout ids
.claude/rules/match-results-and-marks.md	The whole "Match results and marks" section, plus operator labels, match colours, and clearing a mark
.claude/rules/match-writes.md	"Merge changes, never drop" and "Write refusal and the clock frame"
.claude/rules/teams-and-lineups.md	Team credit, bout row names, lineup vacancy, lineups and kachinuki, carried lineups, lineup saves, member stamps, migration, drafts
.claude/rules/eligibility-and-queue.md	Competitor eligibility, send back to queue
.claude/rules/store.md	Startup writability check, store transactions, cache invalidation, competition directory creation
.claude/rules/workbook.md	Excel layout, team block bout rows, workbook owners, Representative Bouts sheet, workbook construction
AGENTS.md, GEMINI.md	A "Domain rules" pointer to .claude/rules/

Test plan

• make go/test passes (lint + security scan + tests)
• New/updated unit tests cover the change: not applicable, no code changed. TestNoDefaultWin* passes with the new files tracked.
• Manual browser verification: not applicable, no web-mobile/ or web/ change
• Screenshots added above: not applicable, no UI change
• Docs updated under docs/: not applicable, no user-facing change
• Docs screenshots and videos recaptured: none changed
• No new console errors or warnings: not applicable
• Every non-blank line of the old CLAUDE.md is present in the new CLAUDE.md or one of the rule files (script check: 0 missing)
• References that crossed the split now name the file they point to
• The guard refuses a Serena edit on internal/engine/match_merge.go until .claude/rules/match-writes.md has been read; checked in a live session and with fake hook inputs

Closes bc-cmrs

🤖 Generated with Claude Code

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