docs: publish Preview 19 dogfood evidence

Export the reviewed allowlisted snapshot from private source commit 05928cebd01b586cf9e9d4b8c8537a7605a6068c. This records the exact candidate, bounded capacity result, stateful migration scratch requirement, authenticated batch identity proof, and immediate live acceptance evidence.

AI-Assisted: OpenAI Codex
Signed-off-by: Cole Speelman <crspeelman@gmail.com>

internal/query/result.go

@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+
+package query
+
+import (
+	"errors"
+
+	"gamertan.com/observatory/internal/schema"
+)
+
+const ResultVersion = 1
+
+var (
+	ErrBudgetExceeded = errors.New("query execution budget exceeded")
+	ErrTypeMismatch   = errors.New("query value does not match its field type")
+)
+
+type Column struct {
+	Field string      `json:"field"`
+	Type  schema.Type `json:"type"`
+	Unit  string      `json:"unit,omitempty"`
+}
+
+// Row values align positionally with Result.Columns. Nil is a missing value;
+// non-nil values use the canonical string form described by the column type.
+type Row struct {
+	Values []*string `json:"values"`
+}
+
+type Statistics struct {
+	ScannedRows  int   `json:"scanned_rows"`
+	MatchedRows  int   `json:"matched_rows"`
+	ScannedBytes int64 `json:"scanned_bytes"`
+	DurationNS   int64 `json:"duration_ns"`
+	Truncated    bool  `json:"truncated"`
+	Approximate  bool  `json:"approximate,omitempty"`
+}
+
+type Result struct {
+	Version int        `json:"version"`
+	Explain Explain    `json:"explain"`
+	Columns []Column   `json:"columns"`
+	Rows    []Row      `json:"rows"`
+	Stats   Statistics `json:"statistics"`
+}