Standardize public metadata, workflows, documentation, and sidecar

[stefan-jansen]

Problem

ml4t/engineer does not satisfy the current stable-library standards. The 2026-09-08
ecosystem collection reports failures in source and PyPI identity, package description,
keywords, canonical project URLs, README installation, links and quality gates, canonical
agent imports, workflow permissions and common CI gates, release-candidate artifact binding,
and deployed documentation identity.

The latest PyPI release is 0.1.3. The public repository is clean at origin/main, recent
default-branch CI is green, and private vulnerability reporting is enabled. The open
Dependabot PR #43 is unrelated and already green.

Required outcome

Bring the release repository and private development sidecar into compliance with the
ecosystem metadata, README, instruction, sidecar, CI, release, security, and documentation
contracts without changing public APIs or weakening existing qualification.

Compatibility

No public API compatibility impact is intended. Preserve the active python-315-polars
exception and the Python 3.12-3.14 support boundary until a separately qualified dependency
update removes it.

Acceptance criteria

• Source metadata uses the canonical author and maintainer identities, factual shared
  description, required keywords, classifiers, and project URLs.
• The README installation and quick start work from a clean built-wheel environment and all
  README links resolve.
• Documentation builds strictly and carries ml4t-library, ml4t-version, and ml4t-commit
  metadata for deployment verification.
• CI and release workflows meet the current shared gates, permissions, immutable-action,
  candidate-manifest, one-time-build, publication-order, and post-deployment checks.
• Agent instruction changes are applied only after explicit approval of the named files.
• The private sidecar has the required topology, verified private origin, a clean synchronized
  default branch, and no lost existing work.
• Ruff, formatting, ty, all tests, package build, clean-wheel import and quick start, strict
  MkDocs, workflow/security checks, and ecosystem qualification pass.

[stefan-jansen]

PRs #47 and #49 completed the metadata, README, workflow, release, documentation, and publication work. The issue remains open because its instruction-file acceptance criterion is still pending the explicit approval required by the ecosystem standard. No public instruction changes have been applied.