Fix/vectorstore error message and docstrings

[ahmedkansulum]

Summary

While reading through VectorStore in src/classifai/indexers/main.py I noticed a few small clarity issues:

• The ValueError raised for unsupported data_type only mentioned ['csv'] and the later error message used {self.data_type} literally (no f-string).
• The module- and class-level docstrings contained a handful of typos (e.g. "Vectoriers mdodule", "curently", "Pacakge", "correpsonding", "metadataq", "vectoiser").

This PR cleans those up without changing any functional behaviour.

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Changes

• Improve the data_type validation message in VectorStore.__init__:

  • Now raises:

    ValueError(
        f"Unsupported data_type='{self.data_type}'. Currently only 'csv' is supported."
    )

  • Behaviour is unchanged: csv remains the only supported data_type.

• Fix the error raised in _create_vector_store_index for unsupported file types:

  • Convert the message to an f-string and make it more explicit:

    ValueError(
        f"File type not supported: '{self.data_type}'. Choose from ['csv']."
    )

• Tidy up docstrings and comments in VectorStore and from_filespace:

  • "Vectoriers mdodule" → "vectorisers module"
  • "the the servers module" → "the servers module"
  • "curently only csv supported" → "currently only 'csv' is supported"
  • "ClassifAI Pacakge" → "ClassifAI package"
  • "correpsonding types" → "corresponding types"
  • "metadataq" → "metadata"
  • "vectoiser" → "vectoriser"

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Rationale

• Makes error messages more informative for downstream users who pass the wrong data_type.
• Avoids confusion from {self.data_type} being rendered literally in the current error.
• Improves readability and professionalism of the public API docstrings with no behavioural change.

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Testing

• Ran:

  make check-python