chore: raise PHPStan to level 9

[dakorpar]

Follow-up to #133. Raises the PHPStan level in make phpstan from 8 to 9.

Level 9 stops accepting mixed where a concrete type is required. Most of the 35 errors traced back to one place: the renderer's config arrays and Nette's getOption() / translate() / getValue() all return mixed, and that value was passed straight into typed APIs.

Renderer config plumbing

• getConfig() / getConfigOverride() now declare their real shape (array<string, mixed[]> and array<int, array<string, mixed[]>>), so fetchConfig() returns an array rather than mixed. It reads them through the getters instead of the SmartObject magic properties — the same call, without the untyped detour.
• configElem() narrows what it reads out of the config instead of trusting it. A non-string element name is ignored, class config is normalized once up front, and an attributes entry that is not an array is skipped rather than fed to foreach.
• Class handling moved into a fetchClasses() helper. CLASS_REMOVE now uses a strict array_filter instead of array_diff, which insisted every class be castable to string — Nette also accepts ['class-name' => bool] class attributes, and the filter handles those without a cast while preserving keys exactly as array_diff did.

Drawing values that came from options

Group labels and validation messages are drawn only when they are actually drawable — HtmlStringable / string / Stringable — instead of handing whatever the option happened to hold to addHtml() or addText(). Previously a group label option holding, say, an int went to addHtml() unchecked.

Inputs

• ChoiceInputTrait only indexes the disabled-values array with something usable as an array key, and compares choice values through a stringifyChoiceValue() helper instead of casting mixed to string.
• CheckboxInput, CheckboxListInput and RadioInput narrow the result of translate() before using it as a caption. CheckboxInput::makeCheckbox()'s $caption doc widened from string|Html|null to string|Stringable|null, which is what it always accepted — setText() takes Stringable, and Html is one.

One real bug: DateInput::validateFormat()

This one was not just a typing gap. The rule passed $input->getValue() into a string parameter, but getValue() returns a DateTime once the input has been validated — so calling the rule in that state was a guaranteed TypeError:

TypeError: DateTimeFormat::validate(): Argument #2 ($timeString) must be of type string, DateTime given

It survived in practice only because BaseControl::validate() calls cleanErrors() first, which DateInput overrides to reset its isValidated flag — so during normal form validation getValue() still returns the raw text. Any other route to the rule crashed.

The rule now checks the format only when there is text to check, and returns true otherwise (an already-parsed value has no textual format to reject; emptiness is the required rule's job). getValue() gained the same guard before handing its value to DateTime::createFromFormat().

Verification

• make phpstan (now -l 9) — no errors
• make cs — clean
• make tests — 173 tests, 266 assertions, all passing

4 new tests: three pin the DateInput rule behaviour (parsed value, unparseable text, null value on a nullable input), one covers class config given as a plain string rather than an array.

Rendered HTML is unchanged — no fixture updates. The existing RendererConfigTest cases for CLASS_SET / CLASS_ADD / CLASS_REMOVE / ATTRIBUTES / CONTAINER all still pass against the rewritten configElem().

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 94.73684% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 97.51%. Comparing base (af238e5) to head (6308fab).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/Inputs/RadioInput.php	80.00%	2 Missing ⚠️
src/Traits/ChoiceInputTrait.php	83.33%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #134      +/-   ##
============================================
+ Coverage     97.48%   97.51%   +0.02%     
- Complexity      313      333      +20     
============================================
  Files            25       25              
  Lines           996     1007      +11     
============================================
+ Hits            971      982      +11     
  Misses           25       25              

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