docs: align historical plans/specs with renamed identifiers (roundTrip -> execute, log schema)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/superpowers/plans/2026-07-26-structured-json-logging.md

@@ -4,14 +4,14 @@
 
 **Goal:** Emit structured JSON logs on stdout for (1) every HTTP API request and (2) every Garmin wrapper subprocess call, correlated by a per-request id — without touching any existing `log.Printf` call site.
 
-**Architecture:** A new `internal/applog` package wraps `log/slog` with a JSON handler plus context helpers (`WithLogger`/`FromContext`). `internal/api` gains a `loggingMiddleware` that logs one line per HTTP request and stashes a request-id-tagged logger into the request context. `internal/garmin`'s `client.go` reads that same logger back out of context (via the `ctx` every `Client` method already receives) inside `roundTrip`, the single funnel point all six Garmin calls go through, logging one line per subprocess round-trip.
+**Architecture:** A new `internal/applog` package wraps `log/slog` with a JSON handler plus context helpers (`WithLogger`/`FromContext`). `internal/api` gains a `loggingMiddleware` that logs one line per HTTP request and stashes a request-id-tagged logger into the request context. `internal/garmin`'s `client.go` reads that same logger back out of context (via the `ctx` every `Client` method already receives) inside `execute`, the single funnel point all six Garmin calls go through, logging one line per subprocess round-trip.
 
 **Tech Stack:** Go stdlib `log/slog` (no new dependency), `github.com/go-chi/chi/v5/middleware` (already-available subpackage of the existing chi dependency).
 
 ## Global Constraints
 
 - Existing `log.Printf`/`log.Fatalf` call sites are untouched — they keep going to stderr, unstructured, exactly as today.
-- Garmin credentials must never be logged. Confirmed safe: `authenticate`/`complete_mfa`/`call` wire params never carry email/password (only env vars at subprocess spawn do) — logging `params` in full is safe everywhere in `roundTrip`.
+- Garmin credentials must never be logged. Confirmed safe: `authenticate`/`complete_mfa`/`call` wire params never carry email/password (only env vars at subprocess spawn do) — logging `params` in full is safe everywhere in `execute`.
 - `gofmt -l .` must report nothing; `go vet ./...` and `go build ./...` must pass.
 
 ---
@@ -480,14 +480,14 @@ git commit -m "feat(api): add structured JSON access log with request-id correla
 ### Task 3: Garmin wrapper call log
 
 **Files:**
-- Modify: `backend/internal/garmin/client.go` (`roundTrip`, `ensureStarted`, all six call sites)
-- Modify: `backend/internal/garmin/client_test.go` (update 3 direct-`roundTrip` calls, add 2 new tests)
+- Modify: `backend/internal/garmin/client.go` (`execute`, `ensureStarted`, all six call sites)
+- Modify: `backend/internal/garmin/client_test.go` (update 3 direct-`execute` calls, add 2 new tests)
 
 **Interfaces:**
 - Consumes: `applog.FromContext` (Task 1).
 - Produces: `func (c *subprocessClient) roundTrip(ctx context.Context, cmdName string, params any) (result json.RawMessage, err error)` (signature change — `ctx` added as first param), `func (c *subprocessClient) ensureStarted(ctx context.Context) error` (signature change — `ctx` added).
 
-- [ ] **Step 1: Update the 3 existing direct-`roundTrip` tests and write the 2 new failing tests**
+- [ ] **Step 1: Update the 3 existing direct-`execute` tests and write the 2 new failing tests**
 
 In `backend/internal/garmin/client_test.go`, add `"bytes"` and `"log/slog"` to the stdlib import block, and add `"geniusrun/backend/internal/applog"` as a new import group.
 
@@ -591,7 +591,7 @@ func TestSubprocessClient_RoundTrip_LogsErrorAtWarnLevel(t *testing.T) {
 - [ ] **Step 2: Run tests to verify they fail**
 
 Run: `cd backend && go test ./internal/garmin/... -run 'TestSubprocessClient_RoundTrip' -v`
-Expected: FAIL — `roundTrip` still takes 2 args, not 3; `applog` import unresolved.
+Expected: FAIL — `execute` still takes 2 args, not 3; `applog` import unresolved.
 
 - [ ] **Step 3: Update `client.go`**
 
@@ -690,7 +690,7 @@ to:
 }
 ```
 
-Replace `roundTrip` entirely. From:
+Replace `execute` entirely. From:
 
 ```go
 // roundTrip sends one request and returns its result payload, or an error