Research corridor: USDC → ZAR (South African Rand)

> Written to the standard set by #33 — read that issue first for the expected level of detail. > **This issue is BLOCKED on Track C landing.** Per the agreed sequencing, corridor research should wait until the analysis-depth metrics (#36, #37, #40, #41, #54) are implemented, so new corridors can be measured with the full toolkit from the start. ## What Research whether a real Stellar-native issuer exists for ZAR (South African Rand) tokenised as a Stellar asset, and whether Horizon path data exists at all before any claim is made about liquidity quality. This is a research task, not a corridor addition. The output is a finding — including a NO-MARKET or "no issuer found" finding — written up the way KESC and GHSC were, not a coverage checkbox. ## Why it matters South Africa has a plausible Stellar ecosystem presence (partnerships with local companies, some Stellar-based projects). But "plausible presence" is not the same as "a usable corridor with a real issuer and path data." This research answers whether the corridor exists at all before any claim is made about its quality. ## Which layer **Layer 1 — observable fact.** The research reads on-chain data and published documents. Nothing is inferred. ## Exactly where the code goes - **Output:** a finding written up in `docs/corridor-measurements.md` or a new `docs/research-ZAR.md` - No code changes — this is research ## Where the data comes from 1. **Stellar SEP-1 resolution:** Does a known ZAR issuer publish a `stellar.toml`? 2. **Horizon account lookup:** Does the issuer account exist and have the expected flags? 3. **Horizon pathfinding:** Does `find_payment_paths` return any routes for USDC → ZAR? 4. **SEP-38:** Does the issuer publish an `ANCHOR_QUOTE_SERVER`? If any step fails, the finding is NO-MARKET or "no issuer found" — and that is a valid, complete result. ## What "unmeasurable" means here If no issuer is found, the finding is "no Stellar-native ZAR issuer identified as of [date]." That is worth stating. Do not fill in a plausible issuer or assume one exists because a company announced a partnership. ## Acceptance criteria - [ ] At least one candidate ZAR issuer is identified and investigated - [ ] The issuer's `stellar.toml` is checked for coherence - [ ] Horizon path data is checked for USDC → ZAR routes - [ ] SEP-38 endpoint is checked - [ ] The finding is written up with evidence (date, source, endpoint) - [ ] If NO-MARKET, the finding says so plainly - [ ] No code changes — research only ## Out of scope Do not change: - Any Go code - The corridor registration in `cmd/wayfared` - The measure workflow - Any existing corridor ## How to verify locally ```bash # Read the finding cat docs/research-ZAR.md 2>/dev/null || cat docs/corridor-measurements.md ``` No build or test needed — this is a research task.