Automate a review finding as a lint or test: Both doors: add src/tui/ screen for the roadmap and its how-to as docs/features/ #12370

The "both doors" check from #10628 already existed, but it let through the cases these four reviews describe. I tightened it so those cases now fail. Nothing in the diff touches web pages, so the tightened rule hasn't been exercised on a real pull, and the forge's full check hasn't run yet.

The rule says a new page in src/web/pages/*.ts needs a terminal screen, a docs/features/<name>.md how-to, or a No door: <why> commit line. It accepted any new file anywhere under src/tui/ as the screen, including helpers and orphans nothing opens, so a pull could pass with no real screen.

What changed

• src/kernel/both_doors.ts:

- A screen now has to be a new file in src/tui/screens/. A helper under src/tui/ui/ no longer counts. - scripts/gate.ts also checks that another module under src/tui imports the new screen, normally via its palette entry. If nothing does, the check says no entry opens that screen. - The failure message still names rule "both doors" and says which door is missing.

• AGENTS.md: the rule's one line now says the screen lives in src/tui/screens/ and is reachable through its palette entry.
• test/both-doors.test.ts: a new test covers a helper that isn't a screen and a screen nothing imports. The message-text assertions were updated for the new wording.

Checks run: test/both-doors.test.ts passes (4 tests), bun scripts/gate.ts is clean, and tsc --noEmit is clean.

What I chose not to do

• Require the screen or doc name to match the page name. Existing pairs diverge (a roadmap screen for the boards page, gpx against geojson), so it would refuse good pulls.
• Catch a new section added to an existing page, as in #12307. A diff can't tell a section from an edit, so that stays with reviewers. The No door: waiver is unchanged.

To try it: add src/web/pages/x.ts and docs/features/x.md with only a new src/tui/ui/x.ts, then run bun scripts/gate.ts. It refuses with rule "both doors".

I merged main into the branch, resolved the conflict, and pushed the result (fdedd59bf).

• Conflict: it was only in AGENTS.md. I kept my reworded "both doors" line, with the screen under src/tui/screens/ and imported by another module. I also kept the new "before/after looks" line that came in from main.
• Gate: the first gate run after the merge flagged three over-long comment lines in src/kernel/both_doors.ts. I rewrapped them to 100 columns. The rewrapped version is what the gate passed on a later run. Before that run I had pushed 8906baceb with the gate still red.
• Checks: bun scripts/gate.ts is clean and bun x tsc --noEmit is clean. test/both-doors.test.ts passes (4 tests). I ran only that file, not the full suite.

The last gate run printed nothing, which I took as a pass. I didn't print its exit code, and the first run's long-line message still appeared in an earlier tail of the same output, so the push may deserve a look at the forge's own check.

The check failed because of a test my change broke: test/both-doors-refusal.test.ts. I fixed it and pushed (45de54f0a). I ran that file and test/both-doors.test.ts locally and they pass (7 tests). bun scripts/gate.ts and tsc --noEmit both exit 0. I did not run the full suite.

Cause: the passing fixture in "a range that adds the page with both doors passes" added a screen that nothing imports. The tightened rule now rejects that, and the check log shows this was the only red test not also red on main.

Fix:

• Fixture: it now includes src/tui/screens/entries.ts, which imports the new screen, so it counts as reachable.
• New test: a screen that nothing imports is refused, and the message says which entry is missing.

The other failures in that log, such as first-screen-line, are red on main as well, so they aren't this pull's. The 16 failed tests I can't account for individually. The log names only two, and I didn't reproduce the rest.

All six review points are fixed, and bun scripts/gate.ts, tsc --noEmit and the three both-doors test files (17 tests) are green. I ran no wider suite.

What changed

• New src/kernel/tui_entry.ts: the reachability check now lives here, out of scripts/gate.ts (item 5). It has three parts:

- specifiers reads double-quoted, single-quoted, bare import "x" and dynamic import("x") forms (item 3). - resolveSpecifier resolves each relative path against its importer and compares it to the screen's real path. ui/traffic.ts importing ./traffic.ts no longer opens screens/traffic.ts (item 1). - readTui returns nothing when src/tui is missing, so the gate no longer crashes there (item 4).

• Who counts as an entry: the importer must be a file that already existed before the pull, and not the screen itself. Two new screens importing each other are refused (item 2).
• imported is required: the bothDoorsProblems parameter in src/kernel/both_doors.ts is no longer optional (item 6).
• scripts/gate.ts: it now just calls these helpers.

Tests

• New test/tui-entry.test.ts covers quote styles, dynamic imports, resolution, the same-basename helper, the same-pull importer and an absent src/tui.
• test/both-doors-refusal.test.ts gains cases for the helper, the pair of new screens, single-quoted and dynamic imports, and a repository with no src/tui before the pull.
• The happy-path fixture now has entries.ts in the base commit, because an entries file added in the same pull no longer counts.
• The unit tests in test/both-doors.test.ts now pass the required imported argument.

Not done: I did not restrict entries to entries.ts and forge.ts only. Any pre-existing file under src/tui that imports the screen by its real path counts. That keeps the rule from refusing the real entry points (local/*, ssh-tell.ts and others) while still closing the orphan and basename holes. Say if you want it narrowed.

There is no web change, so nothing to try on the preview.

The gate failure is fixed and pushed as dbe7f6b5b. The comment above bothDoorsProblems in src/kernel/both_doors.ts is now wrapped under 100 columns.

bun scripts/gate.ts and bun x tsc --noEmit pass, and test/both-doors.test.ts passes (4 tests). The gate only passed after I committed the change, so it appears to read committed content. scripts/fast.ts returned exit 2 because scripts/gate.ts is in the diff, so I ran the covering test file by hand. I did not run the full suite.

This PR adds a rule to the both-doors check: a pull that adds a page now also needs an added terminal screen that something opens. It comes from the #12369 finding: a screen nobody can open is not a door. A pull that adds a page still needs a how-to under docs/features/ as well, or a No door: line in a commit message.