docs: initialize project wiki from production hardening session

12 pages covering architecture, findings, and metrics from the
rotatingMachine + machineGroupControl hardening work:

- Overview: node inventory, what works/doesn't, current scale
- Architecture: 3D pump curves, group optimization algorithm
- Findings: BEP-Gravitation proof (0.1% of optimum), NCog behavior,
  curve non-convexity, pump switching stability
- Metrics: test counts, power comparison table, performance numbers
- Knowledge graph: structured YAML with all data points and provenance
- Session log: 2026-04-07 production hardening
- Tools: query.py, search.sh, lint.sh

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

wiki/SCHEMA.md

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+# Project Wiki Schema
+
+## Purpose
+LLM-maintained knowledge base for this project. The LLM writes and maintains everything. You read it (ideally in Obsidian). Knowledge compounds across sessions instead of being lost in chat history.
+
+## Directory Structure
+```
+wiki/
+  SCHEMA.md          — this file (how to maintain the wiki)
+  index.md           — catalog of all pages with one-line summaries
+  log.md             — chronological record of updates
+  overview.md        — project overview and current status
+  metrics.md         — all numbers with provenance
+  knowledge-graph.yaml — structured data, machine-queryable
+  tools/             — search, lint, query scripts
+  concepts/          — core ideas and mechanisms
+  architecture/      — design decisions, system internals
+  findings/          — honest results (what worked AND what didn't)
+  sessions/          — per-session summaries
+```
+
+## Page Conventions
+
+### Frontmatter
+Every page starts with YAML frontmatter:
+```yaml
+---
+title: Page Title
+created: YYYY-MM-DD
+updated: YYYY-MM-DD
+status: proven | disproven | evolving | speculative
+tags: [tag1, tag2]
+sources: [path/to/file.py, commit abc1234]
+---
+```
+
+### Status values
+- **proven**: tested and verified with evidence
+- **disproven**: tested and honestly shown NOT to work (document WHY)
+- **evolving**: partially working, boundary not fully mapped
+- **speculative**: proposed but not yet tested
+
+### Cross-references
+Use `[[Page Name]]` Obsidian-style wikilinks.
+
+### Contradictions
+When new evidence contradicts a prior claim, DON'T delete the old claim. Add:
+```
+> [!warning] Superseded
+> This was shown to be incorrect on YYYY-MM-DD. See [[New Finding]].
+```
+
+### Honesty rule
+If something doesn't work, say so. If a result was a false positive, document how it was discovered. The wiki must be trustworthy.
+
+## Operations
+
+### Ingest (after a session or new source)
+1. Read outputs, commits, findings
+2. Update relevant pages
+3. Create new pages for new concepts
+4. Update `index.md`, `log.md`, `knowledge-graph.yaml`
+5. Check for contradictions with existing pages
+
+### Query
+1. Use `python3 wiki/tools/query.py` for structured lookup
+2. Use `wiki/tools/search.sh` for full-text
+3. Read `index.md` to find relevant pages
+4. File valuable answers back into the wiki
+
+### Lint (periodically)
+```bash
+bash wiki/tools/lint.sh
+```
+Checks: orphan pages, broken wikilinks, missing frontmatter, index completeness.
+
+## Data Layer
+
+- `knowledge-graph.yaml` — structured YAML with every metric and data point
+- `metrics.md` — human-readable dashboard
+- When adding new results, update BOTH the wiki page AND the knowledge graph
+- The knowledge graph is the single source of truth for numbers
+
+## Source of Truth Hierarchy
+1. **Test results** (actual outputs) — highest authority
+2. **Code** (current state) — second authority
+3. **Knowledge graph** (knowledge-graph.yaml) — structured metrics
+4. **Wiki pages** — synthesis, may lag
+5. **Chat/memory** — ephemeral, may be stale