chore(config): governance and config foundation (#292)

* chore(config): governance and config foundation (PR #272 split 1/6)

Add repository governance and configuration files:
- CODEOWNERS: review authority model
- ISSUE_TEMPLATE: Copilot task template
- PULL_REQUEST_TEMPLATE: comprehensive review checklist
- .env.example: environment variable documentation
- .tool-versions: asdf/mise compatibility (Node 20, Python 3.12)
- .gitignore: expanded coverage (build, test, Python, tmp)
- .markdownlint.json: add MD009 trailing whitespace rule
- VERSION: 0.1.0

This is PR 1 of 6 from the PR #272 decomposition plan.
Dependency chain: PR-1 → PR-2 → PR-3 → PR-4/5/6 (parallel)

* chore(config): remove fork-specific CODEOWNERS from upstream PR

CODEOWNERS references @alfraido86-jpg (fork owner). Submitting this to
upstream would override @affaan-m's review authority. CODEOWNERS belongs
in the fork only, not in upstream contributions.

Ref: SAM finding F9 (run-048 audit)

* chore: address CodeRabbit review feedback on PR #292

- Scope markdownlint config to repo files (globs pattern)
- Add pre-commit hook checkbox to PR template

Ref: CodeRabbit review on PR #292

* fix(config): address CodeRabbit nitpicks N2 and N3

N2: Move pre-commit hooks checkbox higher in security checklist.
N3: Replace global MD009 disable with scoped config (br_spaces: 2).

* fix(config): use recursive glob for node_modules exclusion (N4)

.markdownlint.json

@@ -1,5 +1,7 @@
 {
+  "globs": ["**/*.md", "!**/node_modules/**"],
   "default": true,
+  "MD009": { "br_spaces": 2, "strict": false },
   "MD013": false,
   "MD033": false,
   "MD041": false,
@@ -14,4 +16,4 @@
   "MD024": {
     "siblings_only": true
   }
-}
+}