Summary

• extract cursor-context and input-action derivation from SuggestionEntrySession into focused helper modules
• extract accepted-suggestion transient state and keydown policy into a dedicated helper module with targeted unit coverage
• keep SuggestionEntrySession focused on orchestration while preserving existing suggestion runtime behavior

Scope

• This PR is a focused first pass on src/adapters/chrome/content-script/suggestions
• It does not complete the broader repo-wide unification/refactor across all src files and modules

Test Plan

• bun run typecheck
• bun test tests/SuggestionEntryPredictionContext.test.ts tests/SuggestionAcceptedState.test.ts tests/SuggestionEntrySession.test.ts
• bun run test