chore: bump version to 0.7.3

[raullenchai]

Summary

• Bump version 0.7.2 → 0.7.3 — ships PR revert: roll back PR #555 in-house diffusion loop; fix tool calls via mlx-vlm passthrough #558 (revert PR feat(diffusion): in-house generation loop for DiffusionGemma (P1) #555 in-house diffusion loop; tool calls on mlx-vlm passthrough).

Release SOP gates (pre-bump)

• G1 release-smoke — PASS
• G3 cli/config fidelity audit — PASS
• G4 make smoke (lint + 1933 unit tests) — PASS 3/3
• G8 parser microbench — PASS (6.78us/call extract, no regression)
• G10 mlx-version-bump scan — SKIP (no mlx-* deps changed since v0.7.2)
• G11 auto-routing escape-hatch tests — PASS 47/47

Live verification

• rapid-mlx share diffusion-gemma-26b-4bit boots clean
• Non-stream + SSE tool-call probes return structured tool_calls (no leaked content)
• Perf parity vs upstream mlx-vlm: 49.5 tok/s (rapid HTTP) vs 53.0 tok/s (mlx-vlm direct) — within HTTP wrapper tax

Post-merge

• Tag v0.7.3, publish to PyPI, Homebrew formula auto-update
• PyPI yank v0.7.2 + delete v0.7.2 GitHub release (DiffusionGemma quality regression from fixed_steps=8 default)

🤖 Generated with Claude Code

[github-actions]

PR #559 validation scorecard

Title: chore: bump version to 0.7.3
Author: raullenchai
Diff: 1 file(s), +1/-1 LOC, blast radius: high

Verdict: MERGE-SAFE

step	status	summary	time
fetch	PASS	1 files, +1/-1 LOC, blast=high	0.7s
test_plan_check	PASS	no checkbox-style test plan found	0.0s
cl_description_quality	PASS	title OK + body has rationale (1013 chars)	0.0s
codex_review	skip	codex CLI not found on PATH (install: npm i -g @openai/codex)	0.0s
supply_chain	PASS	no hooks touched, no suspicious patterns, deps clean	8.1s
lint	skip	skipped (gating predicate returned False)	0.0s
targeted_tests	skip	skipped (gating predicate returned False)	0.0s