Updating the readme and intro doc page ahead of v0.8 release

[johnjasa]

Update README and docs intro page

Reorganizes and expands the README and docs/intro.md to:

• reorder content blocks to match user expectations
• better describe H2Integrate's capabilities as a hybrid systems engineering design and technoeconomic analysis tool.

Section 1: Type of Contribution

• Feature Enhancement
  • Framework
  • New Model
  • Updated Model
  • Tools/Utilities
  • Other (please describe):
• Bug Fix
• Documentation Update
• CI Changes
• Other (please describe):

Section 2: General PR Checklist

• PR description thoroughly describes the new feature, bug fix, etc.
• Added tests for new functionality or bug fixes
• Tests pass (If not, and this is expected, please elaborate in the Section 6: Test Results)
• Documentation
  • Docstrings are up-to-date
  • Related docs/ files are up-to-date, or added when necessary
  • Documentation has been rebuilt successfully
  • Examples have been updated (if applicable)
• CHANGELOG.md
  • At least one complete sentence has been provided to describe the changes made in this PR
  • After the above, a hyperlink has been provided to the PR using the following format:
    "A complete thought. [PR XYZ]((https://github.com/NatLabRockies/H2Integrate/pull/XYZ)", where
    XYZ should be replaced with the actual number.

Section 3: Related Issues

N/A

Section 4: Impacted Areas of the Software

Section 4.1: New Files

N/A

Section 4.2: Modified Files

• README.md
  • Reorganized section order: badges/summary, installation (PyPI + link to docs), expanded capabilities overview, publications, citation. Removed inline source install instructions in favor of a docs link.
• docs/intro.md
  • Expanded opening description, updated technology list, added active development areas, moved citation to bottom before auto-API docs.
• CHANGELOG.md
  • Added entry for this PR.

Section 5: Additional Supporting Information

N/A

Section 6: Test Results, if applicable

N/A — documentation-only changes.

Section 7 (Optional): New Model Checklist

N/A