[No QA] Docs updates for E/A#96654 Company card CSV column auto-mapping behavior

[MelvinBot]

Explanation of Change

Help site follow-up to [Payment due @abdulrahuman5196] Improve column auto-mapping when the file structure is different, which changed how the company card spreadsheet import pre-fills its field mappings.

Before that PR, each column auto-detected its own field independently and a saved layout from the previous upload was restored by column position, so re-importing a differently structured file could pre-select the same field on two columns or point a field at an unrelated column. Now the whole mapping is computed in one pass: the headers of the file you just uploaded come first, the saved layout is only a positional fallback for fields the headers don't identify, and it can never override a header match or repeat a field.

The article described the old behavior — "Previously mapped fields auto-fill to save time" — which no longer explains what an admin sees on the mapping screen, and it never documented that mappings are pre-filled from the file's column headers at all. This PR updates docs/articles/new-expensify/connect-credit-cards/Import-Company-Card-Transactions-From-a-Spreadsheet.md to match:

• Adds a ## How Expensify fills in your field mappings section covering header-based detection, the one-column-per-field rule, the saved-layout fallback, and columns left on Ignore.
• Updates step 7 of the import steps to say to review the pre-filled mappings.
• Rewrites the auto-fill note under ## How to upload additional transactions to an existing card feed.
• Updates the ## Can I change field mappings after importing transactions? FAQ and adds two FAQs for the questions this behavior raises: why fields arrive already filled in, and why a field mapped last time can come back empty.
• Adds field/column mapping keywords for retrieval.

All field and button labels used (Card number, Card name, Date, Merchant, Amount, Currency, Unique ID, Ignore, Import, Add cards, Import transactions from file, Import spreadsheet) were verified against the strings the app renders in src/languages/en.ts. A live-UI pass got as far as the Add cards button but couldn't reach the mapping screen — the add-cards flow requires an account-validation magic code, and file upload isn't drivable on the web test harness.

Fixed Issues

$ #96654
PROPOSAL:

Tests

// TODO: The human co-author must fill out the tests you ran before marking this PR as "ready for review"
// Please describe what tests you performed that validates your changed worked.

• Verify that no errors appear in the JS console

Offline tests

QA Steps

// TODO: The human co-author must fill out the QA tests you ran before marking this PR as "ready for review".
// Please describe what QA needs to do to validate your changes and what areas do they need to test for regressions.

• Verify that no errors appear in the JS console

PR Author Checklist

• I linked the correct issue in the ### Fixed Issues section above
• I wrote clear testing steps that cover the changes made in this PR
  • I added steps for local testing in the Tests section
  • I added steps for the expected offline behavior in the Offline steps section
  • I added steps for Staging and/or Production testing in the QA steps section
  • I added steps to cover failure scenarios (i.e. verify an input displays the correct error message if the entered data is not correct)
  • I turned off my network connection and tested it while offline to ensure it matches the expected behavior (i.e. verify the default avatar icon is displayed if app is offline)
  • I tested this PR with a High Traffic account against the staging or production API to ensure there are no regressions (e.g. long loading states that impact usability).
• I included screenshots or videos for tests on all platforms
• I ran the tests on all platforms & verified they passed on:
  • Android: Native
  • Android: mWeb Chrome
  • iOS: Native
  • iOS: mWeb Safari
  • MacOS: Chrome / Safari
• I verified there are no console errors (if there's a console error not related to the PR, report it or open an issue for it to be fixed)
• I followed proper code patterns (see Reviewing the code)
  • I verified that comments were added to code that is not self explanatory
  • I verified that any new or modified comments were clear, correct English, and explained "why" the code was doing something instead of only explaining "what" the code was doing.
  • I verified any copy / text that was added to the app is grammatically correct in English. It adheres to proper capitalization guidelines (note: only the first word of header/labels should be capitalized), and is either coming verbatim from figma or has been approved by marketing (in order to get marketing approval, ask the Bug Zero team member to add the Waiting for copy label to the issue)
• If a new code pattern is added I verified it was agreed to be used by multiple Expensify engineers
• I followed the guidelines as stated in the Review Guidelines
• I tested other components that can be impacted by my changes (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar are working as expected)
• If a new CSS style is added I verified that:
  • A similar style doesn't already exist
  • The style can't be created with an existing StyleUtils function (i.e. StyleUtils.getBackgroundAndBorderStyle(theme.componentBG))
• If new assets were added or existing ones were modified, I verified that:
  • The assets are optimized and compressed (for SVG files, run npm run compress-svg)
  • The assets load correctly across all supported platforms.
• If the PR modifies code that runs when editing or sending messages, I tested and verified there is no unexpected behavior for all supported markdown - URLs, single line code, code blocks, quotes, headings, bold, strikethrough, and italic.
• If the PR modifies a generic component, I tested and verified that those changes do not break usages of that component in the rest of the App (i.e. if a shared library or component like Avatar is modified, I verified that Avatar is working as expected in all cases)
• If the PR modifies a component related to any of the existing Storybook stories, I tested and verified all stories for that component are still working as expected.
• If the PR modifies a component or page that can be accessed by a direct deeplink, I verified that the code functions as expected when the deeplink is used - from a logged in and logged out account.
• If the PR modifies the UI (e.g. new buttons, new UI components, changing the padding/spacing/sizing, moving components, etc) or modifies the form input styles:
  • I verified that all the inputs inside a form are aligned with each other.
  • I added Design label and/or tagged @Expensify/design so the design team can review the changes.
• I added unit tests for any new feature or bug fix in this PR to help automatically prevent regressions in this user flow.
• If the main branch was merged into this PR after a review, I tested again and verified the outcome was still expected according to the Test steps.

Screenshots/Videos

Android: Native

Android: mWeb Chrome

iOS: Native

iOS: mWeb Safari

MacOS: Chrome / Safari

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@Gonals, please review the files changed and confirm they reflect the current behavior. Then post a new comment saying @MelvinBot mark this PR as ready for review.

[OSBotify]

A preview of your ExpensifyHelp changes have been deployed to https://b822dc73.helpdot.pages.dev ⚡️

Updated articles:

• articles/new-expensify/connect-credit-cards/Import-Company-Card-Transactions-From-a-Spreadsheet