feat(settings/git): expose editable commit-message prompt in Git settings

[Dimillian]

Motivation

• Provide a user-editable commit-message prompt used by the built-in commit-message generator so teams can customize the template (and preserve the existing generated-message behavior).
• Surface the current prompt in the Settings → Git panel and offer Save/Reset controls consistent with other settings fields.
• Ensure both the app and the daemon use the stored template when building prompts, with a safe default fallback.

Description

• Added a settings editor UI to the Git section: a textarea with Save and Reset buttons and dirty/saving state handling (src/features/settings/components/sections/SettingsGitSection.tsx, src/features/settings/components/SettingsView.tsx).
• Persisted a commitMessagePrompt field through frontend types/normalization and defaults, and added DEFAULT_COMMIT_MESSAGE_PROMPT helper (src/types.ts, src/features/settings/hooks/useAppSettings.ts, src/utils/commitMessagePrompt.ts).
• Updated shared backend prompt builder to accept a template and fall back to the default when the template is empty, and wired the app and daemon to read commit_message_prompt from app settings when composing the final commit-message prompt (src-tauri/src/shared/codex_aux_core.rs, src-tauri/src/codex/mod.rs, src-tauri/src/bin/codex_monitor_daemon.rs, src-tauri/src/types.rs).

Testing

• Ran npm run lint with no reported errors.
• Ran npm run test and the test suite completed successfully (439 passed).
• Ran npm run typecheck (tsc --noEmit) which completed successfully.
• Ran cargo check in src-tauri which failed in this environment due to a missing system dependency (glib-2.0 via pkg-config), not due to code errors.

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Codex Task

[Dimillian]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. What shall we delve into next?

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