[contursofran]

Fixes #708

What changed

• internal/app/chatview/suggest.go: the popup takes a query at the caret (QueryAt) for "/" and "@"; one popup, two sources (Slash, new Path PathSource). Lists are kept per terminal, and for "@" per typed folder. FilterPaths: paths with a part that starts with the text first, then paths that hold it, at most 50. An insert replaces only "@text" up to the caret; a folder goes in as "@dir/" and the popup stays open.
• internal/app/chatview/composer.go: stores the caret as the field builds.
• internal/review/tree.go: Repo.KnownFiles (git ls-files --cached --others --exclude-standard, sorted).
• internal/app/chat.go: pathSource / listPaths read off the UI thread: the git files and their folders, without files deleted in the work tree, with a nested repo listed once; outside git, a plain read of the typed folder (Repo.Entries).
• Docs: the Path popup section in docs/spec/ChatView.md, and D279.
• The diff is ~510 lines; about half of that is tests.

Tests

• Unit: TestQueryAtCaret, TestFilterPathsOrderAndCap, TestAtInsertsAFile, TestAtInsertsAFolderAndStaysOpen, TestInsertKeepsTheTextAfterTheCaret, TestAtWithNoMatchSaysSo, TestListPathsInGit, TestListPathsOutsideGitReadsTheTypedFolder, TestListPathsOfAnEmptyFolder (temp folders only).
• e2e: go test -tags e2e -run TestChatPathPopup ./cmd/contr passes.
• see.sh: new fixture chat-paths, Dark and Light checked by eye.

Pre-check

1. Tests: each test failed with its change undone: prefix-first order and the cap (FilterPaths), no space after a folder (AtInsertsAFolder), text after the caret (InsertKeeps), TextNoPath (AtWithNoMatch), the "@" check (QueryAt), the non-git fallback (ListPathsOutside), deleted-file skip and the nested-repo dedupe (ListPathsInGit).
2. Plan: every brief item is done.
3. Contract: label "suggestions" is reused; the new text is "No files match"; D279.
4. Up to date: main is merged in. No other open PR touches these files (Spawn: a Claude worker gets the PATH of the spawning process (#728, D282) #729 is spawn only).
5. Diff: read; no debug output left.
6. Coverage: every acceptance line of Chat: autocomplete file paths with @ in the composer #708 is done.
7. Duties: suggestOpen became query, which handles "/" the same way (the slash tests pass).
8. Evidence: the PNGs were taken after the last code commit.