chore: complete FIX-G-004 + bump v0.4.0 (5-state trust model release)

[typelicious]

Summary

Release prep for capacium-models v0.4.0 — consolidates all changes since v0.2.0 (tagged 2026-05-24) and closes the FIX-G-004 datetime.utcnow() gap that was missed in the original Stream G codemod.

What's included in v0.4.0

Source	Change
Direct push (62670bd)	5-state trust model migration (audited → pending_review; deprecated added)
PR #2	TRUST_BADGES dict + get_trust_badge() helper
PR #2	test_models.py migrated from v1 4-state to v2 5-state vocabulary
This PR	datetime.utcnow() → datetime.now(timezone.utc) in models.py (6 occurrences)
This PR	pyproject.toml version 0.2.0 → 0.4.0
This PR	CHANGELOG.md v0.4.0 entry

Breaking changes for downstream consumers

• TrustState.AUDITED is removed — use TrustState.PENDING_REVIEW instead. Database rows with trust_state='audited' are normalized via normalize_legacy_state().
• VALID_TRANSITIONS updated for 5-state graph; DEPRECATED end-of-life state added.

Verification

• PYTHONPATH=src pytest tests/test_models.py → 55 passed
• grep -rn "datetime.utcnow" src/ → 0 occurrences
• No DeprecationWarning: datetime.datetime.utcnow() under Python 3.14
• Ruff clean

Test plan

• CI green (pytest 3.10/3.11/3.12)
• After merge: tag v0.4.0 on main (manual until release workflow exists)
• Publish to PyPI (manual or via new release workflow — to be decided in launch coordination)
• Verify pip install capacium-models==0.4.0 works in clean venv

Process note

The 5-state migration commit (62670bd) landed on main without a PR. This release is the first tag covering those changes. CHANGELOG documents the irregular trail.

[dev-bot-capacium]

Code review for PR #3 (chore: complete FIX-G-004 + bump v0.4.0).

Scope: Release-prep PR consolidating capacium-models changes since v0.2.0:

• 5-state trust model migration (already on main via direct push 62670bd)
• TRUST_BADGES + get_trust_badge() helper (PR #2, merged)
• test_models.py migrated to v2 vocabulary (PR #2)
• This PR: FIX-G-004 completion (datetime.utcnow → now(timezone.utc) in models.py); pyproject.toml v0.2.0 → v0.4.0; CHANGELOG.md v0.4.0 entry.

Files reviewed:

• src/capacium_models/models.py — 6× datetime.utcnow().isoformat() → datetime.now(timezone.utc).isoformat() (lines 74, 165, 215, 289, 326, 352); import extended to from datetime import datetime, timezone. Functionally equivalent — produces timezone-aware UTC datetimes instead of naive (deprecated in Py 3.12+, removed in future).
• pyproject.toml — version 0.2.0 → 0.4.0. Skip-by-1 from 0.2.0 to 0.4.0 documented in CHANGELOG Process Notes (5-state migration that landed via 62670bd direct push is captured retroactively in this release entry).
• CHANGELOG.md — comprehensive v0.4.0 entry with Breaking Changes / New Features / Bug Fixes / Test Migration / Process Notes sections.

Local verification:

• PYTHONPATH=src pytest tests/test_models.py → 55 passed
• grep -rn datetime.utcnow src/ → 0 occurrences
• No DeprecationWarning: datetime.datetime.utcnow() under Python 3.14

Remote CI: 3/3 SUCCESS (test 3.10/3.11/3.12).

Note: Approval via dev-bot-capacium per explicit maintainer authorization. PR work was guided by v2 Fix-PRD launch-prd.md §4 Phase 1 reviewed and approved by maintainer prior to implementation. Side-finding (FIX-G-004 completion gap) folded into this PR per maintainer request rather than separate cleanup PR.

Approved.