feat(capturehttp): POST /capture REST adapter + OAuth2 + origin resolver (#53)

The HTTP door for the capture capability. Thin: authenticate → derive
trust-zone origin → decode → capture.Service → map receipt to status.

- Auth mirrors the chassis Bearer precedence (static token wins, then Dex
  JWT) but returns the resolved principal + auth path, which the chassis
  middleware hides — capture needs the principal to derive the origin.
  Depends on a small Validator interface (the chassis *JWTValidator
  satisfies it) so the JWT/origin path is testable without a live JWKS.
- OriginResolver maps principal → trust zone: static-token caller and
  allowlisted JWT subjects → sovereign; every other principal → us-nexus
  (fail safe, so the I1 gate refuses confidential by default). Principal
  and origin are server-set on the input, overwriting any body the caller
  sent.
- HTTP status: 200 all-ok / dry-run, 207 partial, 502 all-failed, 403 on
  the I1 refusal, 400 on fail-closed validation.
- Wired in main behind the same static+JWT credentials as /mcp, reusing
  the MCP server's graph-wired brain store (one implementation) and the
  classification tags (#50). Mounts only when a Gitea tracker is
  configured. Sovereign JWT principals via BRAIN_CAPTURE_SOVEREIGN_PRINCIPALS.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

ingestion/internal/capturehttp/handler.go

@@ -0,0 +1,211 @@
+// Package capturehttp is the REST adapter for the capture use-case: the
+// POST /capture door (#53). It is deliberately thin — authenticate, derive
+// the trust-zone origin from the authenticated principal, decode the
+// request, call capture.Service, map the receipt to an HTTP status. No
+// business logic lives here; the I1 gate, validation, and orchestration
+// are all in the use-case.
+package capturehttp
+
+import (
+	"context"
+	"crypto/subtle"
+	"encoding/json"
+	"errors"
+	"net/http"
+	"strings"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/capture"
+)
+
+// Validator validates a Bearer JWT and returns its subject. The chassis
+// *auth.JWTValidator satisfies it (including its nil-receiver "disabled"
+// behaviour), and tests can substitute a fake without a live JWKS.
+type Validator interface {
+	Validate(ctx context.Context, rawToken string) (string, error)
+}
+
+// Handler serves POST /capture.
+type Handler struct {
+	svc             *capture.Service
+	validator       Validator // nil ⇒ JWT auth disabled
+	staticToken     string    // "" ⇒ static auth disabled
+	staticPrincipal string    // principal name attributed to static-token callers
+	resolver        OriginResolver
+}
+
+// New constructs a capture HTTP handler. staticToken callers are
+// attributed to staticPrincipal (a sovereign homelab identity); JWT
+// callers are attributed to their token subject.
+func New(svc *capture.Service, validator Validator, staticToken, staticPrincipal string, resolver OriginResolver) *Handler {
+	if staticPrincipal == "" {
+		staticPrincipal = "local-cli"
+	}
+	return &Handler{
+		svc:             svc,
+		validator:       validator,
+		staticToken:     staticToken,
+		staticPrincipal: staticPrincipal,
+		resolver:        resolver,
+	}
+}
+
+// wire types — the POST /capture request body.
+type request struct {
+	Context  contextBody   `json:"context"`
+	Insights []insightBody `json:"insights"`
+	Tickets  []ticketBody  `json:"tickets"`
+	Summary  *summaryBody  `json:"summary,omitempty"`
+	DryRun   bool          `json:"dry_run"`
+}
+
+type contextBody struct {
+	Harness        string `json:"harness"`
+	SessionRef     string `json:"session_ref"`
+	Fidelity       string `json:"fidelity"`
+	Actor          string `json:"actor"`
+	Classification string `json:"classification"`
+}
+
+type insightBody struct {
+	Text          string `json:"text"`
+	Wing          string `json:"wing"`
+	Hall          string `json:"hall"`
+	SupersedeSlug string `json:"supersede_slug,omitempty"`
+}
+
+type ticketBody struct {
+	Repo   string `json:"repo"`
+	Action string `json:"action"`
+	Number int    `json:"number,omitempty"`
+	Title  string `json:"title,omitempty"`
+	Body   string `json:"body,omitempty"`
+}
+
+type summaryBody struct {
+	Title        string   `json:"title"`
+	Body         string   `json:"body"`
+	ReposTouched []string `json:"repos_touched,omitempty"`
+}
+
+// ServeHTTP authenticates, derives origin, runs the use-case, and maps the
+// result to an HTTP status.
+func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	principal, viaStatic, ok := h.authenticate(r)
+	if !ok {
+		http.Error(w, "unauthorized", http.StatusUnauthorized)
+		return
+	}
+
+	var req request
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		return
+	}
+
+	in := req.toInput()
+	// Principal and origin are server-derived — overwrite anything the
+	// caller may have tried to put in the body.
+	in.Context.Principal = principal
+	in.Context.Origin = h.resolver.Resolve(principal, viaStatic)
+
+	rec, err := h.svc.Capture(r.Context(), in)
+	switch {
+	case errors.Is(err, capture.ErrSovereigntyRefused):
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": err.Error()})
+		return
+	case err != nil:
+		// Pre-write validation failure (fail-closed).
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
+		return
+	}
+	writeJSON(w, statusFor(rec), rec)
+}
+
+// authenticate mirrors the chassis Bearer precedence (static wins, then
+// JWT) but returns the resolved principal and whether the static path was
+// taken — the chassis middleware hides both, and capture needs them to
+// derive the origin.
+func (h *Handler) authenticate(r *http.Request) (principal string, viaStatic, ok bool) {
+	raw, found := strings.CutPrefix(r.Header.Get("Authorization"), "Bearer ")
+	if !found || raw == "" {
+		return "", false, false
+	}
+	if h.staticToken != "" && subtle.ConstantTimeCompare([]byte(raw), []byte(h.staticToken)) == 1 {
+		return h.staticPrincipal, true, true
+	}
+	if h.validator != nil {
+		if sub, err := h.validator.Validate(r.Context(), raw); err == nil && sub != "" {
+			return sub, false, true
+		}
+	}
+	return "", false, false
+}
+
+func (b request) toInput() capture.CaptureInput {
+	in := capture.CaptureInput{
+		Context: capture.CaptureContext{
+			Harness:        b.Context.Harness,
+			SessionRef:     b.Context.SessionRef,
+			Fidelity:       b.Context.Fidelity,
+			Actor:          b.Context.Actor,
+			Classification: b.Context.Classification,
+		},
+		DryRun: b.DryRun,
+	}
+	for _, i := range b.Insights {
+		in.Insights = append(in.Insights, capture.Insight{
+			Text: i.Text, Wing: i.Wing, Hall: i.Hall, SupersedeSlug: i.SupersedeSlug,
+		})
+	}
+	for _, t := range b.Tickets {
+		in.Tickets = append(in.Tickets, capture.Ticket{
+			Repo: t.Repo, Action: t.Action, Number: t.Number, Title: t.Title, Body: t.Body,
+		})
+	}
+	if b.Summary != nil {
+		in.Summary = &capture.Summary{
+			Title: b.Summary.Title, Body: b.Summary.Body, ReposTouched: b.Summary.ReposTouched,
+		}
+	}
+	return in
+}
+
+// statusFor maps a receipt to an HTTP status: 200 all-ok (or dry-run),
+// 207 partial, 502 everything-failed.
+func statusFor(rec capture.CaptureReceipt) int {
+	if rec.DryRun {
+		return http.StatusOK
+	}
+	var ok, fail int
+	for _, i := range rec.Insights {
+		count(&ok, &fail, i.OK)
+	}
+	for _, t := range rec.Tickets {
+		count(&ok, &fail, t.OK)
+	}
+	if rec.Summary != nil {
+		count(&ok, &fail, rec.Summary.OK)
+	}
+	switch {
+	case fail == 0:
+		return http.StatusOK
+	case ok == 0:
+		return http.StatusBadGateway // every persistence attempt failed
+	default:
+		return http.StatusMultiStatus // 207: partial success
+	}
+}
+
+func count(ok, fail *int, isOK bool) {
+	if isOK {
+		*ok++
+	} else {
+		*fail++
+	}
+}
+
+func writeJSON(w http.ResponseWriter, status int, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	_ = json.NewEncoder(w).Encode(v)
+}