Server form: extract useConnectionTest, useServerDelete and useIdentityFile hooks #857

Goal

The three self-contained flows of the server form (connection test with host-key trust, delete with preview, identity-file checks and keychain conversion) each live in one hook, so the form component holds fewer unrelated states.

Context

apps/smart-ssh-community/frontend/src/components/ServerForm.tsx has 2,025 lines. The component function ServerForm spans :268–1997 with 55 useState and 10 useEffect. It renders two complete forms: the local pseudo-server (<Tabs at ~:1012, panels general :1020 and notes :1071) and a remote server (<Tabs at ~:1116, panels general :1134, connection :1207, security :1709, notes :1942), plus extension tabs (renderExtensionPanels :451). State groups on develop: loading/dirty tracking (loaded, dirty :283–286, loadServer :509, buildInput :687, handleSubmit :718, save :747); field values (name, host, port, username, groupId, jumpHost, tags, tagDraft, auth :342–350); identity file facts and keychain conversion (identityFacts* :355–362, convert* :366–370, handleConvertToKeychain :824, key-import prompt importPromptOpen/importError/importSavedId :401–405, finishKeepingPath :786); sudo password (:373–379, handleClearSudoPassword :794); security policy (postIngestPolicy, aiInjectionCheckEnabled, secondOpinionAvailable :380–391); tabs and validation (requestedTab, openedExtTabs, invalidTabs, reportValidityPending, tabsServerId :413–420, collectInvalidTabs :467); delete (deleting, deletePreview, secretsLeftBehind :489–495, handleDeleteClick :845, handleConfirmDelete :855); connection test (testing, testResult, testDialog, pendingHostKey :497–504, runTest :877, cancelTest :921, closeTestDialog :929, handleTrustAndRetest :934); local notes and tags (:293–321, :956–984). Helpers before the component: authKindLabels, AuthFormState, authStateFromKind, toAuthMethodInput, IdentityFileFacts (:80–267); exported TestResultBadge (:1997, imported by TestConnectionDialog.tsx). Tests: ServerForm.test.tsx and 7 ServerForm.*.test.tsx files (about 63 tests). Line numbers are from develop before the colour-token migration and may shift slightly.

End state of the series: no file over 800 lines, no function component over 400 lines, at most 12 useState per component; parts under src/components/serverForm/.

Requirements

• src/components/serverForm/useConnectionTest.ts: testing, testResult, testDialog, pendingHostKey, runTest, cancelTest, closeTestDialog, handleTrustAndRetest.
• src/components/serverForm/useServerDelete.ts: deleting, deletePreview, secretsLeftBehind, handleDeleteClick, handleConfirmDelete.
• src/components/serverForm/useIdentityFile.ts: identity file facts (loading, error, debounced check), keychain conversion state and handler, and the key-import prompt state with finishKeepingPath.
• The hooks receive what they need (server id, current input via a getter, callbacks such as onDeleted) as parameters; they do not read the form's other state directly.
• Move IdentityFileFacts to src/components/serverForm/IdentityFileFacts.tsx and TestResultBadge to src/components/serverForm/TestResultBadge.tsx (re-export from ServerForm.tsx or update TestConnectionDialog.tsx).

Acceptance Criteria

• The three hooks exist under src/components/serverForm/ with hook tests (renderHook): connection test success, failure and host-key prompt → trust → retest; delete preview → confirm → callback, delete error; identity file check success, check failure, conversion success and error.
• ServerForm has at least 18 fewer useState calls than before this issue.
• The test count of ServerForm*.test.tsx (plus the new hook tests) is not lower than before; existing tests pass without changes to their assertions.
• npm run lint, npx vitest run, npm run build and npm run test:e2e pass.

Technical Notes

• Pure refactoring: no change to behaviour, visible text, i18n keys, CSS classes, data-testids, ARIA attributes, keyboard handling, invoked Tauri commands or listened events. Behaviour changes, if you find a bug, go into a separate issue (mention it in the PR).

• Colour classes in these files are being migrated to theme tokens in a separate issue that must be merged first; keep exactly the classes that are on develop when you start.

• Exports that other files or tests import from the original file keep working: either update the importers or re-export from the original path. The extension API (src/extensions/*, src/api.ts, src/components/ui) does not change.

• Tests: count it(/test( in the listed test files before and after; the number must not decrease. Tests may move next to an extracted unit, but their assertions stay the same. Tests drive the user-visible behaviour through FileBrowserPanel/ChatPanel/ServerForm as today.

• New code comments in English; existing German comments may move unchanged.

• No filter, risk, redaction or credential logic is touched (frontend only).

• Gate: npm run lint, npx vitest run, npm run build in apps/smart-ssh-community/frontend, plus npm run test:e2e if a browser test covers the component.

• Host-key trust in the connection test is security-relevant: the hook must call exactly the same API as today, only after the user's explicit "trust" decision.

Spec impact: none

Related Work

• Previous: Server form: the key-import prompt uses DialogFrame (focus trap, Escape, labelled title) #852; next: Server form: useServerFormModel reducer for field values, loading and dirty tracking #861, Server form: separate LocalServerForm and RemoteServerForm with GeneralTab, ConnectionTab, SecurityTab and NotesTab #865