chore: bootstrap repo scaffolding (M0.1)

Bootstraps §1.2 scaffolding (README, CONTRIBUTING, CODEOWNERS, CHANGELOG, PR + issue templates, LICENSE, CI workflow, release workflow, commitlint, cliff, .editorconfig, .gitignore, .env.example) and ships a proprietary all-rights-reserved LICENSE naming both founders.

Refs: M0.1

cliff.toml

@@ -0,0 +1,39 @@
+# git-cliff config — generates release notes from Conventional Commits.
+# Preset: keepachangelog.
+
+[changelog]
+header = """
+# Changelog
+
+All notable changes to this repo. Format: [Keep a Changelog](https://keepachangelog.com/).
+"""
+body = """
+{% if version %}\
+## [{{ version | trim_start_matches(pat="v") }}] - {{ timestamp | date(format="%Y-%m-%d") }}
+{% else %}\
+## [Unreleased]
+{% endif %}\
+{% for group, commits in commits | group_by(attribute="group") %}
+### {{ group | upper_first }}
+{% for commit in commits %}
+- {{ commit.message | upper_first }}\
+{% endfor %}
+{% endfor %}
+"""
+trim = true
+
+[git]
+conventional_commits = true
+filter_unconventional = true
+commit_parsers = [
+  { message = "^feat",     group = "Added" },
+  { message = "^fix",      group = "Fixed" },
+  { message = "^perf",     group = "Changed" },
+  { message = "^refactor", group = "Changed" },
+  { message = "^docs",     group = "Docs" },
+  { message = "^chore",    skip = true },
+  { message = "^ci",       skip = true },
+  { message = "^test",     skip = true },
+]
+filter_commits = true
+tag_pattern = "v[0-9]*"