#17530: refactor(sessions): centralize session status field extraction

## Summary - Introduces `SESSION_STATUS_FIELD_NAMES` const array as single source of truth for the 12 common session status fields that were duplicated across ~8 consumer types - Adds `pickSessionStatus(entry)` to extract common fields via spread and `applySessionStatusFields(target, source)` to conditionally merge them - Refactors `GatewaySessionRow`, `SessionRow`, `SessionInfo`, `SessionInfoEntry`, and `SessionListRow` to extend the shared type instead of redeclaring each field - Net removal of ~73 lines of duplicated type/extraction code - Adding a new session status field now requires one string in the const array instead of touching ~8 files ## Files changed | File | Change | |------|--------| | `src/config/sessions/session-status.ts` | **NEW** — const array, types, two utilities | | `src/config/sessions/session-status.test.ts` | **NEW** — unit tests | | `src/config/sessions.ts` | Barrel re-export | | `src/gateway/session-utils.types.ts` | `GatewaySessionRow` extends `Partial<SessionStatusFields>` | | `src/gateway/session-utils.ts` | `listSessionsFromStore` uses `pickSessionStatus` spread | | `src/commands/sessions.ts` | `SessionRow` extends `Partial<SessionStatusFields>`, `toRows` uses `pickSessionStatus` | | `src/tui/tui-types.ts` | `SessionInfo` extends `SessionStatusFieldsNullable` | | `src/tui/tui-session-actions.ts` | `SessionInfoEntry` extends `SessionStatusFieldsNullable`, `applySessionInfo` uses `applySessionStatusFields` | | `src/tui/tui-command-handlers.ts` | `null` → `undefined` for token field clearing (type alignment) | | `src/agents/tools/sessions-helpers.ts` | `SessionListRow` extends `Partial<SessionStatusFields>` | ## Design decisions - `model`/`modelProvider` intentionally excluded from shared fields — each consumer resolves them differently - `SessionStatusFieldsNullable` variant handles JSON-RPC boundaries where `null` values appear - `sessions-list-tool.ts` left unchanged — its defensive type-guarded extraction is correct for JSON-RPC boundary data - `contextTokens` in `applySessionInfo` stays manual due to 3-way fallback logic ## Test plan - [x] New unit tests for `pickSessionStatus` and `applySessionStatusFields` - [x] `pnpm build` — clean - [x] `pnpm check` (format + tsgo + lint) — clean - [x] `pnpm test` — all 815 test files, 6016 tests pass ## Contribution checklist - [x] Local validation: `pnpm build && pnpm check && pnpm test` — all passing - [x] Focused scope: single refactoring theme (deduplicate session status fields) - [x] Clear "what" + "why" in description - [x] AI-assisted (Claude Code) — fully tested, code reviewed and understood by author 🤖 Generated with [Claude Code](https://claude.com/claude-code) <!-- greptile_comment --> <h3>Greptile Summary</h3> This PR centralizes 12 session status fields (`systemSent`, `abortedLastRun`, `thinkingLevel`, `verboseLevel`, `reasoningLevel`, `elevatedLevel`, `responseUsage`, `inputTokens`, `outputTokens`, `totalTokens`, `totalTokensFresh`, `contextTokens`) that were previously duplicated across ~8 consumer types into a single `SESSION_STATUS_FIELD_NAMES` const array with derived types and two extraction utilities (`pickSessionStatus`, `applySessionStatusFields`). - Removes ~73 lines of duplicated type declarations and manual field extractions across `GatewaySessionRow`, `SessionRow`, `SessionInfo`, `SessionInfoEntry`, and `SessionListRow` - `model`/`modelProvider` are correctly excluded from the shared set since each consumer resolves them differently - The `null` → `undefined` change in `tui-command-handlers.ts` is safe — all consumers use loose equality (`== null`) or nullish coalescing (`??`) - Computed overrides in `session-utils.ts` (`totalTokens`, `totalTokensFresh`) correctly appear after the `pickSessionStatus` spread - The `contextTokens` 3-way fallback in `applySessionInfo` correctly runs after `applySessionStatusFields` and overrides as needed - New unit tests cover edge cases including `null`/`undefined` inputs and falsy values (`false`, `0`) <h3>Confidence Score: 5/5</h3> - This PR is a clean, well-tested refactor that reduces duplication without changing observable behavior. - Pure type-level and extraction-logic refactoring with no behavioral changes to runtime logic. Computed overrides (totalTokens, totalTokensFresh, contextTokens) are correctly preserved after the spread. The null-to-undefined change is safe given consumer patterns. New unit tests cover the utility functions thoroughly. All 10 changed files were reviewed and no issues were found. - No files require special attention _{Last reviewed commit: 928ea9e} <!-- greptile_other_comments_section --> <!-- /greptile_comment -->