Add Ideas feature (controller, UI, repository, and routing)

[ercmine]

Motivation

• Add in-session idea management so users can list, create, delete, and paginate ideas for a session.
• Expose a dedicated Ideas UI and navigation from the existing session screen so ideas are discoverable and actionable.
• Surface friend-submitted ideas across UI components using a reusable badge and reuse that indicator in deck-related views.

Description

• Introduces IdeasState and IdeasController with initLoad, refresh, loadMore, createIdea, and deleteIdea behaviors and pagination support.
• Adds UI components: IdeasPage, AddIdeaSheet, IdeaListTile, FriendIdeaBadge, and lightweight deck widgets DeckCard and CardDetailsSheet for displaying plans and friend-idea badges.
• Wires up providers and routing by adding ideasControllerProvider, updating ideasRepository.listIdeas to accept cursor and limit, and registering a new route '/sessions/:id/ideas' in router.dart.
• Updates SessionPage to navigate to the ideas page and implements form validation and phone normalization in the add-idea sheet.

Testing

• No automated tests were run for these changes.

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Codex Task

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Keep submit lock until post-create refresh completes

createIdea clears isSubmitting before awaiting refresh, which re-enables the Add button while the first submission is still in progress; on a slow network, users can tap again and send duplicate create requests because the re-entry guard only checks isSubmitting. This can create duplicate ideas for a single intended submission.

Useful? React with 👍 / 👎.

[chatgpt-codex-connector]

Only show delete success after a confirmed delete

The page always shows the "Idea deleted" snackbar after calling deleteIdea, but deleteIdea handles failures internally and does not report success/failure to the caller. If the API delete fails (or refresh fails after delete), users still see a success message, which gives incorrect feedback about data state.

Useful? React with 👍 / 👎.