Align reference consumer with base-cli 0.5.0

[codeforester]

Summary

Refs #47.

• move package metadata and lock resolution to base-cli>=0.5.0,<0.6;
• update compatibility and draft-release evidence workflows to test the 0.5.x line;
• update README, compatibility, adoption, and starter documentation;
• document the 0.5.0 telemetry success status contract and update the consumer regression assertion;
• retain the explicit released-wheel/source-checkout boundary.

Validation

• base-cli 0.5.0 candidate wheel built from base-cli main;
• ./tests/validate.sh: 65 passed;
• package build/validation: passed;
• uv lock --check: passed;
• shell syntax and diff checks: passed.

Release prerequisite

The 0.5.0 base-cli package is merged on base-cli main but is not yet published to PyPI. This PR is intentionally draft and must remain unmerged until the immutable base-cli 0.5.0 release exists, then the lockfile should be refreshed against the published artifact and the hosted compatibility matrix rerun.

[codeforester]

Reviewed head 6461695 against #47 (Refs, so the issue stays open). The content is right for 0.5.0: ranges move to >=0.5.0,<0.6 in package metadata and both workflows, the docs follow, and the telemetry assertion changes status=UNSET → status=OK to match the 0.5.0 success-status contract. But this can't merge yet:

1. Blocked on publication. Every install job fails with No matching distribution found for base-cli<0.6,>=0.5.0, and PyPI's latest is 0.4.3. 0.5.0 is merged in base-cli (#423) but not published. Keep this as a draft until the release checklist completes.
2. uv.lock was hand-edited, not resolved. The base-cli 0.5.0 entry claims source = { registry = "https://pypi.org/simple" } but has no sdist/wheels entries or hashes. That isn't a lock uv would write, and it drops hash pinning for the main dependency. After 0.5.0 is on PyPI, regenerate with uv lock --upgrade-package base-cli and check uv lock --check in CI.

[codeforester]

Registry source with no sdist/wheels/hashes: this entry was edited by hand, since 0.5.0 isn't on PyPI yet. Regenerate it with uv lock after publication so the dependency is hash-pinned again.

[codeforester]

Reviewed and verified the two blockers:

• The registry currently exposes Base-CLI only through 0.4.3, so the hosted 0.5.0 compatibility jobs cannot resolve the declared range.
• uv lock --upgrade-package base-cli fails with the same unsatisfiable >=0.5.0,<0.6 constraint.

I am deliberately not replacing the hand-edited 0.5.0 lock entry with another fabricated or local-path lock. The correct follow-up is to publish Base-CLI 0.5.0, regenerate uv.lock from the registry with uv lock --upgrade-package base-cli, verify hashes and hosted compatibility, then promote this PR from draft. PR #48 remains draft and unmerged.