#11109: fix(tui): prefer config contextTokens over persisted session value

## Summary Fixes #11067 The TUI footer was showing `0/200k` tokens instead of the user's configured `contextTokens` (e.g., 1M) because the persisted session value from previous runs was taking precedence over the config. ## Problem When a session runs, `contextTokensUsed` is calculated (often 200k from model lookup or `DEFAULT_CONTEXT_TOKENS`) and saved to the session entry. On subsequent TUI refreshes, this persisted `entry.contextTokens` was being used instead of `defaults.contextTokens` from the user's config. ## Solution Changed the priority order in `applySessionInfo` to prefer config-level `contextTokens` over the persisted session value: ```typescript // Before: entry?.contextTokens ?? defaults?.contextTokens // After: defaults?.contextTokens ?? entry?.contextTokens ``` This ensures the user's explicit configuration (`contextTokens: 1000000`) is respected in the TUI display. ## Testing - [x] Verified the logic change - [ ] Manual testing with 1M context config --- 🤖 AI-assisted: This fix was developed with Claude. The bug was identified by tracing the data flow from config → session storage → TUI display. <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This PR updates the TUI session-info merge logic so that `agents.defaults.contextTokens` from the current config is preferred over a persisted `entry.contextTokens` value stored in the sessions file. The change is localized to `src/tui/tui-session-actions.ts` in `applySessionInfo`, which feeds `state.sessionInfo.contextTokens` used by the footer token display (`src/tui/tui.ts`). Net effect: users who set a larger context window in config (e.g. 1M) will see that reflected in the footer instead of an older model-derived/persisted context value (often 200k). <h3>Confidence Score: 5/5</h3> - This PR is safe to merge with minimal risk. - The change is a one-line precedence swap in a nullish-coalescing chain that only affects how the TUI displays the context window size; it doesn’t alter persistence or core session behavior. No new control flow, side effects, or API contracts are introduced. - No files require special attention <!-- greptile_other_comments_section --> _{(3/5) Reply to the agent's comments like "Can you suggest a fix for this @greptileai?" or ask follow-up questions!} <!-- /greptile_comment -->