ci: run Lemonade-dependent checks when LEMONADE_VERSION changes

[kovtcharov]

Why this matters

A Lemonade version bump edits only src/gaia/version.py (LEMONADE_VERSION), which the install-lemonade action reads to provision the runners. But every Lemonade-dependent workflow was path-filtered to feature code (src/gaia/rag/**, llm/**, agents, cpp/**, …) and excluded version.py — so the one change that swaps the Lemonade build on the runners triggered none of the tests that exercise it.

That's the gap that let Lemonade 10.7.0 → 10.8.1 land while the embedding model nomic-embed-text-v2-moe is broken on the bundled llama-server: the embeddings/RAG/API/E2E checks simply never ran on the bump. The break only surfaced days later on unrelated PRs (including a .docx RAG PR) whose authors had no idea it wasn't their change.

Root cause of the embedding break is upstream, not ours — a Vulkan-backend regression on AMD GPUs since llama.cpp build b6524 (llama.cpp #16301, open), surfaced in Lemonade #612 / #941. This PR doesn't fix that; it makes our CI catch that class of regression on the bump PR instead of silently shipping it.

This adds src/gaia/version.py and .github/actions/install-lemonade/** to the push + pull_request path triggers of every Lemonade-using workflow (embeddings, rag, lemonade-server, api, agent-sdk, agent-mcp-server, behavior-e2e, examples, gaia-cli-windows, sd, build_cpp).

Test plan

• All 11 workflows parse as valid YAML; every paths: block (21 total) now contains src/gaia/version.py (verified programmatically)
• Reviewer sanity check: the next LEMONADE_VERSION bump PR should now trigger Test Lemonade Embeddings, Test RAG, API Tests, Agent SDK/MCP/Behavior, Lemonade Server Smoke, SD, and C++ build — confirm in that PR's checks list
• (Separately) the embedding regression itself needs a Lemonade/llama-server fix or a pin to a pre-b6524 build — tracked upstream, out of scope here

[github-actions]

Verdict: Approve ✅

This closes a real CI gap: a Lemonade version bump only edits version.py, but every Lemonade-dependent workflow was path-filtered to feature code and excluded it — so the bump that swaps the Lemonade build on the runners triggered none of the tests that exercise it (exactly how the broken nomic-embed-text-v2-moe embedding shipped unnoticed). Adding version.py and the install-lemonade action to the triggers fixes that.

Coverage is complete and correct: the 11 workflows changed are precisely the 11 that reference install-lemonade — none missed, none extraneous. The only thing worth a glance is a harmless redundancy (three workflows already match version.py via a broader src/** glob); no functional impact, no change required.

🔍 Technical details

Verification performed:

• All 11 workflows parse as valid YAML after the change.
• grep -rl install-lemonade .github/workflows/ returns exactly the 11 files in this PR — full coverage, no Lemonade-using workflow left out.
• install-lemonade/action.yml:34 does read LEMONADE_VERSION from src/gaia/version.py, so the path trigger matches the actual dependency.

🟢 Minor — redundant version.py entry where a broad glob already covers it (test_agent_sdk.yml, test_gaia_cli_windows.yml, test_examples.yml)
These three already path-filter on src/** (or src/gaia/**), which already matches src/gaia/version.py, so the explicit src/gaia/version.py line is a no-op in them. The install-lemonade/** addition is still meaningful there (it lives outside src/). Harmless and arguably improves readability/intent — fine to leave as-is. No action needed.

Strengths

• Surgical, scope-clean change — only the paths: blocks touched, both push and pull_request triggers updated consistently across every file.
• PR description nails the why: leads with user-observable impact (silent embedding regression shipped because the bump ran no tests) and is honest that the upstream Vulkan/llama.cpp break is out of scope — this PR makes CI catch the class of regression, not fix the regression.
• Test plan is verifiable and was actually run (YAML validity + every paths: block now contains version.py).