v0.3.0

What's Changed

• ci: GitHub-release-only pipeline; harden plugin_upload.py by @rpintassilgo in #27
• docs(metadata): set plugin homepage and use plain "CO2" by @rpintassilgo in #28
• docs(readme): add Support section for commercial inquiries by @rpintassilgo in #29
• docs(readme): fix QGIS min version, parametrize CAPEX, link docs site by @rpintassilgo in #31
• test: add unit suite + CI, fix Makefile (phase 1 of #10) by @rpintassilgo in #33
• docs: reflect QGIS 4 support and the qgis.PyQt Qt binding by @rpintassilgo in #34
• docs(contributing): add coding standards and issue-label taxonomy by @rpintassilgo in #35
• docs(contributing): drop the LLM co-author trailer note by @rpintassilgo in #36
• docs(claude): sync CLAUDE.md with post-refactor tree by @rpintassilgo in #49
• feat(lcp): configurable GRASS r.cost RAM via a Settings dialog by @rpintassilgo in #51
• feat(lcp): optionally save r.cost/r.drain diagnostic rasters by @rpintassilgo in #53
• chore: delete dead Plugin Builder / Sphinx scaffolding by @rpintassilgo in #54
• fix(task-manager): guard task callbacks against destroyed dialog on unload by @rpintassilgo in #55
• fix(crossings): wire Crossings signals once, not twice by @rpintassilgo in #56
• perf(capex): throttle precise-mode logging + make fast-mode logging consistent by @rpintassilgo in #57
• chore(release): 0.3.0 by @rpintassilgo in #58

Full Changelog: v0.2.1...v0.3.0