feat(01-01): add Phase 1 invariant verification scripts

Three executable bash scripts under tools/ that Wave 0 and every
subsequent Phase 1 plan's <automated> block rely on:

- verify-no-version-literals.sh (INFRA-01 SC#2 / D-09): no literal
  library/plugin version strings in any *.gradle.kts. Excludes
  build-logic/build.gradle.kts (needs asDependency() literals) and
  top-level project-version assignments ("^version = \"x.y.z\"")
  which are artifact metadata, not library pins.
- verify-shared-pure.sh (INFRA-06 / D-19): shared/commonMain must
  not import Ktor/Compose/SQLDelight. Returns OK if the directory
  does not exist yet (pre-scaffold tolerance for Plan 07).
- verify-ios-flags.sh (INFRA-03 / D-18): both K/N iOS binary flags
  present in gradle.properties.

All three use bash (#!/usr/bin/env bash + set -euo pipefail) and
are marked chmod +x. Scripts exit 0 against the current repo state.

tools/verify-shared-pure.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+# Enforces INFRA-06 / D-19: shared/commonMain must not import Ktor, Compose, SQLDelight.
+# Runs grep against shared/src/commonMain/ only. Allowed imports: kotlin.*, kotlinx.serialization, kotlinx.datetime.
+set -euo pipefail
+if [ ! -d shared/src/commonMain ]; then
+    echo "OK: shared/src/commonMain does not exist yet (pre-scaffold)."
+    exit 0
+fi
+VIOLATIONS=$(grep -rn -E '^import[[:space:]]+(io\.ktor|androidx\.compose|org\.jetbrains\.compose|app\.cash\.sqldelight)' shared/src/commonMain/ 2>/dev/null || true)
+if [ -n "$VIOLATIONS" ]; then
+    echo "ERROR: shared/commonMain has forbidden imports:" >&2
+    echo "$VIOLATIONS" >&2
+    exit 1
+fi
+echo "OK: shared/commonMain is pure."