AGENTS.md, CONTRIBUTING.md and CLAUDE.md describe the superseded 10.0.0 rename plan #66

Problem

AGENTS.md, CONTRIBUTING.md ("Issues", "Labels", "Branches and releases") and CLAUDE.md ("Tracking") still describe the plan the decision of 2026-10-19 (#36) replaced:

• main is 10.0.0, the rename under new ids; release/5.x takes only loud fixes and ends at the v10.0.0 tag
• a silent fix found before 10.0.0 "waits for 10.0.0"; the "after 10.0.0" rule is what lets a silent fix reach the LTS line
• net11 holds the .NET 11 retarget; release/10.x is cut at v10.0.0

None of that will happen: 5.5.0 is the last 5.x minor with a change of its own, release/5.x is cut at v5.5.0 and is the EF Core 10 LTS line until 2028-11, and main becomes CodoMetis.EFCore.SchemaKit (#37, #38). ROADMAP.md, #35, #36 and SECURITY.md already say so.

release/5.x is cut from the v5.5.0 tag, so it inherits these files. The next silent bug found on the LTS line then has a documented route of "wait for 10.0.0", a release that will never exist. CLAUDE.md is the canonical guide for agents working here, and it states the wrong line policy.

The mechanics are fine: pr-hygiene.sh already requires a silent fix to go in a minor with a ### Changed answers row, on any line.

Fix

Rewrite the three documents' line and branch rules after #36 and ROADMAP.md section 3:

• two lines: EFCore.ComplexIndexes 5.x on EF Core 10 (release/5.x from the v5.5.0 tag, fixes only, to 2028-11) and SchemaKit 11.x on EF Core 11 (main)
• from 5.5.0 a silent fix ships as a minor with ### Changed answers, a loud fix in a patch or a minor
• a fix for code both lines have goes to main first and is cherry-picked with -x; a fix for code only 5.x has goes straight to release/5.x

Lands before the tag, so release/5.x starts with the right rules.