chore: align project with dev-charter updates

Merge commit 'e39634791e61f44d29549643ecd282b14fa8e67e'

Squashed 'docs/dev-charter/' changes from a309e10..cc3c3dd

Merge pull request #2 from y-marui/claude/refactor-python-tooling-BDUY7

refactor: migrate from Poetry to uv

docs: fix CI badge URL in README files

docs: add README, LICENSE, and update AI_CONTEXT with charter sync

Squashed 'docs/dev-charter/' changes from 916b3f2..a309e10

Merge commit '9cd59c65f4dacecc31890eb78a6bc8314f68a80a'

Merge pull request #1 from y-marui/claude/generate-ai-context-Ln04u

test: add placeholder test to prevent pytest exit code 5

fix: remove unused pytest import in conftest.py

docs: reflect all dev-charter files into template

docs: generate AI_CONTEXT.md from dev-charter and project files

Squashed 'docs/dev-charter/' content from commit 916b3f2