fix(codemods): wrap bare function references passed to onAction

[mfal]

action-prop-to-on-action renamed the prop and left the value alone, so its
apply asked for a manual pass over every call site. That instruction was
answering the wrong question.

Deciding whether a reference needs wrapping needs type information — whether
controller.close declares a parameter is not in the source. Performing the
wrap does not: () => fn() calls exactly what Action would have called, and
onAction takes no arguments. So the wrap fixes the reference that needed it
and changes nothing for the rest, which removes the decision instead of
answering it.

What the codemod does now

Wrapped — a bare reference:

• a plain identifier, action={close} → onAction={() => close()}
• a member expression rooted in an identifier or this,
  action={controller.close}, action={store.modal.controller.close},
  action={this.handleSave}

Left alone:

• an arrow function and a function expression — already the handler
• a call: makeHandler(), close.bind(controller), useCallback(close, []).
  These produce the handler, so wrapping would call the factory on every
  trigger and throw its result away. This is the one shape where a naive
  "wrap everything" is plainly wrong
• anything that is not one reference: isOpen ? close : open,
  onClose ?? noop, controller?.close

The wrap targets the surviving onAction whatever the prop was called before,
so a consumer who renamed by hand — or ran the previous version of this codemod
— gets the wrap on a second run. That also keeps it idempotent: its own output
is an arrow function, which it skips.

Where unconditional wrapping is not a no-op

Two cases, neither decidable from the source. apply and the entry body name
both.

1. A handler that reads the argument Action forwards. Action does
   forward the trigger's event — Button.onPress → action.execute(...args) →
   ActionExecutionBatch.executeBatch(...args) → the handler. A handler
   declaring that parameter as optional or rest type-checks both before and
   after the wrap, so it silently stops receiving the event. Nothing documents
   onAction as receiving an argument (ActionProps.onAction's JSDoc says only
   "the function executed when the action is triggered"), and no Flow-internal
   handler reads one — but a consumer relying on it gets no warning. This is the
   only silent case I found.
2. A possibly-undefined reference, onAction={props.onAction}. undefined
   is a valid value for the prop; calling it is not. The wrap turns something
   TypeScript accepted into something it rejects — loudly, at the call site, so
   it is a compile error to fix rather than a regression to find.

entry.md

The body's closing paragraph claimed the codemod "deliberately does not wrap",
and apply told the reader (or agent) to check every site by hand. Both
rewritten to what the codemod now does, plus the two cases above. MIGRATION.md
and migrations.generated.ts regenerated from it.

Verification

• pnpm nx test:unit codemods — 319 pass, 13 of them this transform's fixtures
  (12 new: bare identifier, member expression, deep chain, this, a value
  already spelled onAction, arrow, function expression, call, conditional /
  ?? / optional chain, alias + namespace import, non-Flow Action and a plain
  <form action>, sibling props)
• pnpm nx test:compile codemods clean
• pnpm lint clean (0 errors; the 71 + 118 warnings are pre-existing)

Overlap with #3047

#3047 (sibling issue #3061) touches the same two generated files,
packages/codemods/src/migrations.generated.ts and
packages/components/MIGRATION.md, for different entries
(renamed-css-export, table-column-width-props) and different hunks. No
source file is shared. Whichever merges second may need
pnpm nx build codemods re-run and the two artifacts recommitted.

fixes #3060

🤖 Generated with Claude Code

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Coverage Report for ./packages/components/

Status	Category	Percentage	Covered / Total
🔵	Lines	78.69%	746 / 948
🔵	Statements	78.57%	763 / 971
🔵	Functions	80.09%	165 / 206
🔵	Branches	70.33%	377 / 536

File Coverage

No changed files found.

Generated in workflow #6616 for commit 9068c68 by the Vitest Coverage Report Action

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Type	URL
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Images:

• docs: ghcr.io/mittwald/flow/docs:pr-3075
• storybook: ghcr.io/mittwald/flow/storybook:pr-3075