Use supervisor-provided options for string app config fields

[kingpanther13]

Proposed change

Multi-value string fields in app configuration always render with an empty
suggestion list, because the selector conversion hard-codes options: []. For
users this means fields like the Samba add-on's "Enabled shares" open an empty
dropdown and valid values must be typed from memory.

home-assistant/supervisor#7023 makes Supervisor include options on string
schema nodes whose match() regex is a simple alternation of literals. This
change passes those through to the select selector so valid values appear as
suggestions. custom_value stays enabled, so free-text entry is unaffected and
validation semantics do not change. Single-value string fields deliberately
keep their text selector even when options are present: the single-value
custom_value picker cannot store an empty string (clearing emits undefined,
which drops the key on save), so converting them would silently change
stored-value semantics. The schema-to-selector mapping for string fields is
extracted into a small util module with unit tests covering each outcome.

This PR functionally depends on home-assistant/supervisor#7023: today's
Supervisor never includes options on string schema nodes, so without that PR
this change is a safe no-op (entry.options is undefined and behavior is
byte-identical to today). Either merge order is safe, but there is no
user-visible effect until the Supervisor counterpart lands.

Screenshots

To be added: before (the current empty suggestion list on the Samba add-on's
"Enabled shares" field) and after (requires running this branch against a
Supervisor that includes home-assistant/supervisor#7023).

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (thank you!)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes Addon config multi-select chip inputs show an empty suggestion list #51510
• This PR is related to issue or discussion:
• Link to documentation pull request:
• Link to developer documentation pull request:
• Link to backend pull request: Expose options from simple alternation match() schemas in UI schema supervisor#7023

Checklist

• I understand the code I am submitting and can explain how it works.
• The code change is tested and works locally.
• There is no commented out code in this PR.
• I have followed the perfect PR recommendations
• Any generated code has been carefully reviewed for correctness and compliance with project standards.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

To help with the load of incoming pull requests:

• I have reviewed two other open pull requests in this repository.

[home-assistant]

Hi @kingpanther13

It seems you haven't yet signed a CLA. Please do so here.

Once you do that we will be able to review and accept this pull request.

Thanks!

[MindFreeze]

LGTM but lets see what happens with the supervisor PR

[kingpanther13]

Closing per the outcome in home-assistant/supervisor#7023: the fix moves into the Samba add-on itself. Step 1 (home-assistant/addons#4717) normalizes stored enabled_shares values to lower case; step 2 (home-assistant/addons#4718) switches the schema to list(), after which the existing select rendering shows the options and #51510 is resolved with no frontend change needed.