docs(plans): add GOAP Wave 2-7 plan with 54 tasks, update audit with 12 new findings

plans/009-cross-runtime-analysis.md

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+# ADR-009: Cross-Runtime Analysis — Python, Rust CLI, and Web UI Parity
+
+## Status
+
+Referenced
+
+## Context
+
+The project maintains three runtimes: Python (primary development, scripts/),
+Rust CLI (high-performance binary, cli/), and Web UI (Next.js, web/). Features
+developed in one runtime often lag behind the others, creating a maintenance
+burden and inconsistent user experience.
+
+## Decision
+
+Track parity gaps explicitly in a living document (this ADR). Close gaps based
+on user impact and maintenance cost:
+
+1. **Rate throttling** → Implement in Rust first (harder to retrofit), port to
+   Python, keep in aiohttp for Web.
+2. **Quality confidence gate** → Implement in all three simultaneously (shared
+   constants).
+3. **Routing features** → Python first (fastest iteration), port to Rust + Web
+   once stable.
+
+## Completed Parity Items
+
+| Feature | Python | Rust | Web | PR |
+|---------|--------|------|-----|----|
+| Quality confidence gate | ✅ | ✅ | ✅ | #341 |
+| Tiered cache TTL | ✅ | ✅ | N/A | #338 |
+| Probabilistic provider skip | ✅ | ✅ | ✅ | #342 |
+| Adaptive per-domain reorder | ✅ | ✅ | N/A | #343 |
+| Rate throttling (token bucket) | ✅ | ✅ | N/A | #358 |
+| Cache pre-warming | ❌ | ✅ | ✅ | #339 |
+
+## Open Parity Gaps
+
+| # | Feature | Python | Rust | Web | Impact |
+|---|---------|--------|------|-----|--------|
+| P1 | `exa_mcp_mistral` combo | ❌ | ❌ | ✅ | Users of Python/Rust CLI miss this query strategy |
+| P2 | Deep research parallel mode | Partial | `--synthesize` only | ✅ | Full parallel mode missing in CLIs |
+| P3 | Budget profiles / presets | N/A | `--profile` flag exists, not wired | N/A | Wire Rust flag to presets |
+| P4 | Preflight routing | `detect_doc_platform()` | Minimal `detectJsHeavy()` | Minimal | Port advanced routing to Rust/Web |
+| P5 | Hedged requests | ✅ | ❌ | ❌ | Performance gap — Python has hedging, Rust/Web sequential |
+| P6 | Routing memory persistence | In-memory only | File persistence | N/A | Python loses state on restart |
+| M7 | Mobile/tablet Playwright in CI | N/A | N/A | ❌ | Mobile regressions undetected |
+
+## Consequences
+
+- Gaps P4-P5 are the highest priority — they directly affect resolution quality
+  and performance.
+- P1 is lower priority — few users rely on the exact `exa_mcp_mistral` combo.
+- P6 is a correctness issue — routing memory is the primary mechanism for
+  learned provider preferences and should be persistent across all runtimes.
+- M7 is a CI gap that should be fixed in the next CI pass (see ADR-013).
+
+## References
+
+- [AUDIT.md](AUDIT.md) — Section 4: Cross-Platform Parity
+- [GOAP_FOLLOWUP.md](GOAP_FOLLOWUP.md) — Wave implementation tracking