feat(mcp): brain_pending + brain_promote tools + REST routes (#38)

Wires the curation primitives into the MCP surface (all three sites:
tools() descriptors, handleCall dispatch, package doc) and registers the
GET /pending + POST /promote REST routes. brain_promote additionally
re-indexes the promoted note into the graph (best-effort), matching the
other write paths. brain_pending is the human-review-queue complement to
the agent-facing brain_write.

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

ingestion/internal/mcp/handlers.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/mathiasbq/hyperguild/ingestion/internal/api"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/brain"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/capture"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/extract"
@@ -81,6 +82,21 @@ func (s *Server) tools() []map[string]any {
 				"path": str("brain-relative path to the note; equivalent to id"),
 			}),
 		},
+		{
+			"name":        "brain_pending",
+			"description": "List notes in brain/raw/ awaiting human promotion to the wiki, oldest-first. Returns filename, created_at, size_bytes, excerpt. The human-review queue complement to brain_promote.",
+			"inputSchema": schema([]string{}, map[string]any{}),
+		},
+		{
+			"name":        "brain_promote",
+			"description": "Promote a brain/raw/ note into brain/wiki/<wing>/<hall>/: rewrites frontmatter (sets wing/hall/promoted_at, preserves created_at + custom fields), deletes the source, rebuilds the wing index, runs auto-tunnel. Errors (without touching the fs) on invalid hall or a slug collision. Returns {path}.",
+			"inputSchema": schema([]string{"filename", "wing", "hall"}, map[string]any{
+				"filename": str("basename in brain/raw/, e.g. 2026-06-01-lejpa-decision.md"),
+				"wing":     str("target wing, e.g. jepa-fx"),
+				"hall":     enum("target hall", halls...),
+				"slug":     str("optional target slug; defaults to filename minus date prefix"),
+			}),
+		},
 		{
 			"name":        "brain_tunnel",
 			"description": "Create an explicit bidirectional [[wikilink]] between two notes in different wings. Idempotent.",
@@ -321,6 +337,40 @@ func (s *Server) brainGet(ctx context.Context, args json.RawMessage) (json.RawMe
 	})
 }
 
+// brainPending lists the raw/ review queue (oldest-first).
+func (s *Server) brainPending(_ context.Context, _ json.RawMessage) (json.RawMessage, error) {
+	pending, err := api.ListPending(s.brainDir)
+	if err != nil {
+		return nil, err
+	}
+	return json.Marshal(map[string]any{"pending": pending})
+}
+
+type brainPromoteArgs struct {
+	Filename string `json:"filename"`
+	Wing     string `json:"wing"`
+	Hall     string `json:"hall"`
+	Slug     string `json:"slug,omitempty"`
+}
+
+// brainPromote moves a raw/ note into the structured wiki (frontmatter
+// rewrite + index + auto-tunnel, all owned by api.PromoteNote) and then
+// re-indexes it into the graph. The human-facing complement to brain_write.
+func (s *Server) brainPromote(ctx context.Context, args json.RawMessage) (json.RawMessage, error) {
+	var a brainPromoteArgs
+	if err := json.Unmarshal(args, &a); err != nil {
+		return nil, fmt.Errorf("parse args: %w", err)
+	}
+	relPath, err := api.PromoteNote(s.brainDir, api.PromoteOptions{
+		Filename: a.Filename, Wing: a.Wing, Hall: a.Hall, Slug: a.Slug,
+	})
+	if err != nil {
+		return nil, err
+	}
+	s.indexInGraph(ctx, "brain_promote", relPath)
+	return json.Marshal(map[string]string{"path": relPath})
+}
+
 // indexInGraph is a best-effort wrapper around graphsync.IndexDoc that
 // logs failures but never propagates them — the underlying write/ingest
 // has already succeeded and the graph is an augmentation, not a