refactor(app): extract server dialog owners

[Astro-Han]

Summary

Extracts owner files from the oversized server selection dialog:

• dialog-select-server-default.ts owns default-server and preview-status hooks
• dialog-select-server-form.tsx owns the add/edit server form
• dialog-select-server-list.tsx owns the server list row/menu rendering
• dialog-select-server-source.test.ts locks the new source boundary

dialog-select-server.tsx drops from 649 LOC on dev to 412 LOC in this PR.

Why

This is a #604 settings-lane frontend governance slice. The server dialog was a single mixed file with state flow, health preview, form UI, list UI, and default-server mutation logic. This PR keeps the state flow in the parent while moving form/list/helper owners into reviewable files.

Related Issue

Part of #604.

Human Review Status

Pending. A human should make the final merge decision after reviewing the final diff and verification evidence.

Review Focus

• Confirm this is a structure-only extraction with no server selection behavior changes.
• Confirm DialogSelectServer still owns mutation/state flow while form/list/default helpers own their local UI/helper responsibilities.
• Confirm the source-contract test protects the new owner boundary without replacing typecheck.

Topology

• Base: dev
• Head: codex/dialog-select-server-owners
• Dependency status: independent flat PR. It does not depend on chore: add frontend architecture governance baseline #667, chore(ui): add shared tool contract export #669, refactor(app): extract timeline staging helper #670-refactor(app): remove orphaned timeline header code #675, refactor(ui): extract session turn changes panel #676-refactor(ui): extract session turn diffs #677, fix(ui): harden theme typography follow-ups #673, refactor(app): extract session share command owner #678, or refactor(app): extract settings general section owners #679.
• Review order: can be reviewed after or alongside refactor(app): extract settings general section owners #679; both are [Task] UI rewrite v2 Area D: settings modular rollout #604 but touch different files.

Touched Files

• packages/app/src/components/dialog-select-server.tsx
• packages/app/src/components/dialog-select-server-default.ts
• packages/app/src/components/dialog-select-server-form.tsx
• packages/app/src/components/dialog-select-server-list.tsx
• packages/app/src/components/dialog-select-server-source.test.ts

Risk Notes

Behavior should be unchanged. Risk is prop wiring between the parent dialog and the extracted form/list owners. No dependency, migration, credential, persistence format, or platform behavior changes are intended.

How To Verify

Install: completed with frozen lockfile
Command: bun install --frozen-lockfile

Focused app test: 2 passed
Command: bun test --preload ./happydom.ts src/components/dialog-select-server-source.test.ts

Typecheck: 8 successful, 8 total
Command: bun run typecheck

Diff check: no whitespace errors
Command: git diff --check && git diff --cached --check

File-size check: dialog-select-server.tsx 649 LOC on dev -> 412 LOC in this PR
Command: wc -l packages/app/src/components/dialog-select-server.tsx packages/app/src/components/dialog-select-server-default.ts packages/app/src/components/dialog-select-server-form.tsx packages/app/src/components/dialog-select-server-list.tsx packages/app/src/components/dialog-select-server-source.test.ts

Behavior e2e smoke: 1 passed
Command: bun --cwd packages/app script/e2e-local.ts -- e2e/app/home.spec.ts --grep "server picker dialog"

CI: required checks passed after rerunning perf-probe-baseline; the first perf run failed on tool-default-open-heavy-bash frame_gap_p95_ms and the rerun passed, so this was treated as perf noise.

Screenshots or Recordings

Not captured. This PR is a structure-only extraction with no intended visual change; the server dialog row/form contracts are covered by source-contract test plus typecheck.

Checklist

• Human review status is stated above as pending, approved, or not required
• I linked the related issue, or stated why there is no issue
• This PR has type, primary area, and priority labels, or I requested maintainer labeling
• I described the review focus and any meaningful risks
• I listed the relevant verification steps and the key result for each
• I did not introduce unrelated refactors, dependencies, generated files, or file changes beyond the stated scope
• I manually checked visible UI or copy changes when needed, with screenshots or recordings
• I considered macOS and Windows impact for platform, packaging, updater, signing, paths, shell, or permissions changes
• I called out docs, release notes, dependencies, permissions, credentials, deletion behavior, generated content, or local file changes when relevant
• I reviewed the final diff for unrelated changes and suspicious dependency changes
• I am targeting dev, and my PR title and commit messages use Conventional Commits in English

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ℹ️ Review info

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Review profile: CHILL

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Run ID: 01c3378f-c734-44b8-a751-47544a0311b0

📥 Commits

Reviewing files that changed from the base of the PR and between a696ede and 814847b.

📒 Files selected for processing (5)

• packages/app/src/components/dialog-select-server-default.ts
• packages/app/src/components/dialog-select-server-form.tsx
• packages/app/src/components/dialog-select-server-list.tsx
• packages/app/src/components/dialog-select-server-source.test.ts
• packages/app/src/components/dialog-select-server.tsx

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/dialog-select-server-owners

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[github-actions]

Suggested priority: P2 (includes user-path files (packages/app/src/components/dialog-select-server-default.ts, packages/app/src/components/dialog-select-server-form.tsx, packages/app/src/components/dialog-select-server-list.tsx, packages/app/src/components/dialog-select-server-source.test.ts, packages/app/src/components/dialog-select-server.tsx)).

P1/P0 are reserved for maintainer confirmation. Please relabel manually if this is a release blocker, security issue, data-loss risk, or updater/runtime failure.

[github-actions]

Perf delta summary

Comparator: pass

Profile / Scenario	interaction median	interaction worst	long task max	tbt	frame gap p95	frame gap max	jank count	cls	status
default / homepage-cold	24 -> 24 (0)	48 -> 32 (-16)	75 -> 68 (-7)	25 -> 18 (-7)	16.8 -> 33.2 (+16.4)	133.4 -> 166.7 (+33.3)	3 -> 3 (0)	0 -> 0 (0)	pass
default / long-session-input-lag	40 -> 48 (+8)	48 -> 56 (+8)	0 -> 0 (0)	0 -> 0 (0)	16.8 -> 16.8 (0)	16.8 -> 16.8 (0)	0 -> 0 (0)	0 -> 0 (0)	pass
default / session-streaming-long	40 -> 40 (0)	72 -> 56 (-16)	0 -> 0 (0)	0 -> 0 (0)	16.8 -> 16.8 (0)	33.4 -> 33.4 (0)	0 -> 0 (0)	0 -> 0 (0)	pass
default / tool-call-expand	16 -> 16 (0)	16 -> 16 (0)	0 -> 0 (0)	0 -> 0 (0)	16.7 -> 16.8 (+0.1)	16.7 -> 16.8 (+0.1)	0 -> 0 (0)	0 -> 0 (0)	pass
default / tool-default-open-heavy-bash	24 -> 32 (+8)	32 -> 32 (0)	64 -> 63 (-1)	14 -> 13 (-1)	50 -> 33.4 (-16.6)	116.7 -> 166.6 (+49.9)	2 -> 2 (0)	0 -> 0 (0)	pass
default / terminal-side-panel-open	48 -> 48 (0)	56 -> 56 (0)	0 -> 0 (0)	0 -> 0 (0)	33.4 -> 33.4 (0)	33.4 -> 33.4 (0)	0 -> 0 (0)	0 -> 0 (0)	pass
default / session-scroll-reading	32 -> 24 (-8)	40 -> 24 (-16)	0 -> 0 (0)	0 -> 0 (0)	16.8 -> 16.7 (-0.1)	16.8 -> 16.7 (-0.1)	0 -> 0 (0)	0.505 -> 0.505 (0)	warn: cls

[gemini-code-assist]

Code Review

This pull request refactors the DialogSelectServer component by extracting its internal logic and UI elements into separate files: dialog-select-server-default.ts (hooks), dialog-select-server-form.tsx (form component), and dialog-select-server-list.tsx (list component). It also adds a unit test to verify the integrity of these extracted parts. Feedback was provided regarding the use of a canonical key function for the server list to ensure compatibility with non-HTTP connections, and a correction was suggested for a syntax error in a Tailwind class string along with a recommendation to use explicit theme token variables for design-system consistency.