feat: operational tooling — signing, versioning, changelog, roadmap (SPEC-001)

Establish GuruConnect's release engineering and project tracking (SPEC-001):
- docs/ scaffold: FEATURE_ROADMAP, ARCHITECTURE_DECISIONS (ADR-001 standalone+contract,
  ADR-002 Gitea Actions + Azure Trusted Signing), docs/specs/SPEC-001, CHANGELOG.
- .gitea/workflows/release.yml: conventional-commit auto-versioning, git-cliff changelog,
  Windows agent build, Azure Trusted Signing via jsign (reusing the shared ACG cert profile),
  Gitea release via REST API. build-and-test.yml is the PR/push gate; deploy.yml de-duplicated.
- server: GET /api/changelog/:component/:version (latest + by-version), path-traversal hardened.
- cliff.toml; server/.env.example documents CHANGELOG_DIR.

Reviewed (Code Review Agent): axum route-conflict blocker fixed; CHANGELOG ordering, toolchain
target, breaking-change parsing, empty-changelog fallback addressed.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

changelogs/.gitkeep

@@ -0,0 +1,8 @@
+# Generated changelog directory.
+#
+# Populated by .gitea/workflows/release.yml on each release:
+#   changelogs/<component>/v<version>.md   per-component, per-version notes
+#   changelogs/LATEST_<COMPONENT>.md       most recent notes for each component
+#
+# Served by the server at GET /api/changelog/:component/{latest,:version}
+# (CHANGELOG_DIR env var points the server at this directory in production).