fix(save): keep the matching lists portable domain knowledge

[tanglearncode]

A context is domain knowledge meant to be handed to a teammate intact. #80 put a hole in that, and this closes it.

What was wrong

The matching lists added in #79 travel inside the bundle. The guidance in #80 told the model to fill routingEntities with "services, repos, ticket ids, error strings, commands, hosts, people".

Hostnames and people are exactly the things that mean nothing on someone else's machine — and "people" contradicts the save command's own standing rule against writing unnecessary personal information. A matching list is the easiest place for a bundle to quietly stop being portable: an absolute path looks like a usefully rare term while it is being written, and is worthless or revealing the moment the context is shared.

Two smaller defects alongside it:

• The hosts disagreed. Claude, Copilot and pi asked for "commands, hosts, people"; Kimi and Codex asked for "commands"; pi's tool schema asked for "commands, hosts". The same work saved from different hosts produced different bundles.
• Nothing enforced any of it. The rule lived only in prose, so compliance was the model's to get right every time.

The fix

One wording on every host, asking for names that belong to the subject: services, components, repositories, ticket ids and prefixes, error strings, product and system names. No hosts. No people.

An explicit portability rule in each document: these lists travel with the context, so no absolute paths, home directories, usernames, personal names, or email addresses, and nothing whose meaning depends on this machine or this person.

The escape hatch stays where it belongs. If the work genuinely is about a particular environment, the profile says so — that is what the profile is for. What changes is that the matching index is not where machine detail goes.

A mechanical filter, so this does not rest on prose. Entries containing a drive letter path, a UNC path, ~/, /home/, /Users/, /root/, or an email address are dropped from both lists at save time. It applies to the lists only; the profile and knowledge folder are untouched, and being unable to search for a context by someone's home directory costs nothing worth having.

Tests

Machine paths in all five shapes are dropped, email addresses are dropped, the rule applies to questions as well as entities — and, the one that keeps the filter honest, ordinary domain terms that merely look technical are kept: src/core/routing.mjs, default_pool_size, billing-postgres:5432, INC-1001, user-service.

The cross-host document sweep now also asserts every host states the portability rule and that none of them asks for hostnames or people again.

Diff coverage: 22 changed lines, 0 uncovered. Full suite 437 passing.