release: prepare ExcelAlchemy 2.1.0

[ruicore]

Summary

This PR prepares the 2.1.0 release of ExcelAlchemy.

It continues the stable 2.x line with internal architecture cleanup, naming improvements, and stronger separation between facade state and single-run import workflow state, while keeping the public import/export workflow API stable.

What changed

Import workflow

• introduce ImportSession as the one-shot import runtime
• move worksheet state, header parsing state, issue tracking, and executor state out of the long-lived ExcelAlchemy facade
• keep ExcelAlchemy.import_data(...) unchanged for users

Config normalization

• add internal config layers:
  • ImporterSchemaOptions
  • ImportBehavior
  • ExporterSchemaOptions
  • ExportBehavior
  • StorageOptions
• normalize internal consumers so they read schema, behavior, and storage options instead of treating config as an all-in-one bus

Metadata layering

• split FieldMetaInfo into clearer internal layers for:
  • declaration metadata
  • runtime binding
  • workbook presentation
  • import constraints
• preserve FieldMeta(...) and ExcelMeta(...) at the public API level

Naming cleanup

• simplify generic type parameter names in the core architecture
• move internal vocabulary from df/header_df toward worksheet_table/header_table
• add excelalchemy.util.converter as the canonical converter module
• keep excelalchemy.util.convertor as a deprecated compatibility shim

Documentation and release prep

• add a 2.1.0 changelog entry
• add a dedicated docs/releases/2.1.0.md release checklist

Compatibility notes

• no public import/export workflow API was removed
• df and header_df remain available as backward-compatible aliases in 2.x
• legacy Minio config remains supported in 2.x
• excelalchemy.util.convertor remains importable in 2.x with a deprecation warning

Verification

• ./.venv/bin/ruff check .
• ./.venv/bin/uv run pyright
• ./.venv/bin/pytest -q

Release intent

After merge, this branch is intended to be tagged and published as:

• v2.1.0

[codecov]

Codecov Report

❌ Patch coverage is 86.78261% with 76 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.27%. Comparing base (26ada7b) to head (b69f155).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
src/excelalchemy/core/alchemy.py	62.96%	28 Missing and 2 partials ⚠️
src/excelalchemy/metadata.py	94.50%	11 Missing ⚠️
src/excelalchemy/core/import_session.py	92.24%	7 Missing and 3 partials ⚠️
src/excelalchemy/util/converter.py	76.31%	6 Missing and 3 partials ⚠️
src/excelalchemy/core/executor.py	69.56%	2 Missing and 5 partials ⚠️
src/excelalchemy/util/convertor.py	0.00%	4 Missing ⚠️
src/excelalchemy/core/headers.py	88.23%	2 Missing ⚠️
src/excelalchemy/core/storage_minio.py	33.33%	0 Missing and 2 partials ⚠️
src/excelalchemy/core/rows.py	90.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #53      +/-   ##
==========================================
+ Coverage   86.04%   86.27%   +0.22%     
==========================================
  Files          46       48       +2     
  Lines        2931     3220     +289     
  Branches      366      370       +4     
==========================================
+ Hits         2522     2778     +256     
- Misses        242      275      +33     
  Partials      167      167              

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