chore: sync .cursor skills from suite

.cursor/skills/research/steps/03_engine-investigation.md

@@ -160,7 +160,7 @@ Tier sources by authority, **prioritize primary sources** (L1 > L2 > L3 > L4). C
 
 **Tool Usage**:
 - Use `WebSearch` for broad searches; `WebFetch` to read specific pages
-- Use the `context7` MCP server (`resolve-library-id` then `get-library-docs`) for up-to-date library/framework documentation
+- Use the `context7` MCP server (`resolve-library-id` then `query-docs` / `get-library-docs`) for up-to-date library/framework documentation. **Mandatory per lead candidate** — see "API Capability Verification" below.
 - Always cross-verify training data claims against live sources for facts that may have changed (versions, APIs, deprecations, security advisories)
 - When citing web sources, include the URL and date accessed
 
@@ -190,6 +190,48 @@ For every component/tool/library/service/pattern/algorithm that may be selected
 - Licensing, security, maintenance, and community-health constraints
 - Exact phrases from the project's restrictions and acceptance criteria combined with the candidate name
 
+**API Capability Verification — Per-Mode (MANDATORY, BLOCKING for lead candidates)**:
+
+**Applicability**: this section applies only when the run is classified as **Technical-component selection** in the SKILL's Research Output Class section, and only to lead candidates that are libraries/SDKs/frameworks/services/protocols/data formats with multiple modes or configurations. For non-technical research (concept comparison, market/policy investigation, knowledge organization, root-cause analysis without tooling commitments), skip this entire sub-section and continue with the rest of Step 2 — the broader candidate implementation-limit search above is sufficient. State the skip explicitly once in `02_fact_cards.md`: `API Capability Verification: not applicable — this run is a Non-technical investigation, no library/SDK/service candidates`.
+
+Most libraries/SDKs/services expose **multiple modes or configurations** (e.g., monocular vs stereo VO, sync vs async API, batch vs streaming inference, write-through vs write-behind cache). Selecting a candidate "because it supports X" without pinning *which mode* the project will use, and *whether that exact mode produces the required outputs from the required inputs*, is the most common silent-failure path in research. A library can support a class of problem in mode A while being unusable for the project's specific configuration in mode B.
+
+For every lead candidate that is a library/SDK/framework/service with multiple modes or configurations, do the following — in this order, before marking the candidate `Selected`:
+
+1. **Pin the exact mode/configuration the project will use.**
+   Derived from the Project Constraint Matrix: which inputs are available (sensor count, sensor types, data shapes, rates), which outputs are required (per `acceptance_criteria.md` and contract files), which hardware/runtime is fixed (per `restrictions.md`). Write this as a single sentence: "We will use `<library>` in `<mode/config>` with inputs `<list>` and expect outputs `<list>` on `<runtime>`." Do not progress past this step on a vague mode description.
+
+2. **Run `context7` (or equivalent docs lookup) for the candidate** — this is **mandatory for every lead library/SDK/framework candidate**, not optional. Minimum three queries per candidate:
+   1. *Mode enumeration*: "What modes/configurations does `<library>` support? List every value of the mode/config enum and what each requires as input."
+   2. *Project's exact mode*: "Show a minimum runnable example of `<library>` in `<the pinned mode>` with `<the project's input shape>`. What does it produce?"
+   3. *Disqualifier probe*: "Does `<library>` `<the pinned mode>` produce `<the required output>`? Are there published limitations of `<the pinned mode>` for `<the project's runtime/hardware>`?"
+
+   For services without context7 coverage, use official docs site + WebFetch on the API reference page + the project's example/tutorial directory in the source repo. Append every consulted URL to `01_source_registry.md`.
+
+3. **Save a Minimum Viable Example (MVE) for the pinned mode.**
+   Append to `02_fact_cards.md` (or a sibling `02_mve_evidence.md`) at least one block per lead library candidate with:
+
+   ```markdown
+   ## MVE — <library> in <pinned mode>
+   - **Source**: <official URL or context7 reference, with date>
+   - **Inputs in the example**: <e.g., 2 calibrated cameras + IMU at 200 Hz>
+   - **Outputs in the example**: <e.g., 6-DoF pose with covariance>
+   - **Project inputs**: <e.g., 1 camera + IMU at 200 Hz>
+   - **Project outputs required**: <e.g., 6-DoF pose with metric translation>
+   - **Match assessment**: ✅ exact match / ⚠️ partial (specify dimension) / ❌ mismatch (specify dimension)
+   - **If ⚠️ or ❌**: cite the official-docs sentence that establishes the mismatch.
+   ```
+
+   If no official example covers the project's exact configuration → the candidate cannot be marked `Selected` based on category fit alone. Status must be `Experimental only` (with required-evidence note) or `Rejected` (when the docs explicitly disqualify the configuration).
+
+4. **Bind every numbered Restriction and Acceptance Criterion to the candidate's pinned mode.**
+   For each numbered line in `restrictions.md` and `acceptance_criteria.md`, decide one of: `Pass` (the pinned mode satisfies it with cited evidence), `Fail` (the pinned mode contradicts it with cited evidence), `Verify` (no evidence either way; deeper investigation required), `N/A` (the line is irrelevant to this component area). Record this in `02_fact_cards.md` under the candidate's MVE block. The structural matrix in Step 7.5 reads from these bindings.
+
+5. **Treat "the same library in a different mode" as a different candidate.**
+   If the project's pinned mode is `Monocular` but the only documented evidence covers `Stereo`, do not silently soften "rotation only" into "rotation + translation". Open a separate candidate row for the Monocular mode, with its own MVE, fit assessment, and disqualifiers. Two modes of one library are two distinct candidates for the purposes of this gate.
+
+**Common silent-failure pattern this guards against**: a fact card paraphrases the docs as "supports A, B, C, D modes" when the docs actually mean "supports A; B; C and D as separate orthogonal modes". A category-level "Selected" decision then carries through every downstream artifact, masking that the project's required A+B combination does not exist as a single mode.
+
 **Search broadening strategies** (use when results are thin):
 - Try adjacent fields: if researching "drone indoor navigation", also search "robot indoor navigation", "warehouse AGV navigation"
 - Try different communities: academic papers, industry whitepapers, military/defense publications, hobbyist forums