#582 Add topic autocomplete to rule creation dialog

[bracyw]

Changes

Replaces the plain text input for the topic field in the add-rule dialog with a PrimeNG AutoComplete component. Topics are fetched from the backend via getAllDatatypes and filtered as the user types, matching case-insensitively against any segment of the "/" delimited path as well as partial paths. forceSelection ensures only valid topics can be submitted.

• Swapped pInputText for p-autoComplete with forceSelection and fluid layout
• Fetches topic list on dialog open via APIService.query with auto-cleanup (filter + take(1))
• Registered AutoCompleteModule globally in main.ts

Notes

The edit-rule dialog does not have a topic field (it only edits expression and debounce time), so no changes were needed there.

Test Cases

• Typing a partial segment like "volt" surfaces all voltage-related topics across BMS, VCU, DTI, etc.
• Typing a partial path like "BMS/Pack" correctly matches topics under that hierarchy
• Selecting a suggestion populates the form with the full topic name
• Typing a non-matching string and blurring clears the field (forceSelection)
• Form validation still requires a non-empty topic before submission

Screenshots

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Closes #582