fix(kyberforge): tell an unparsable Contributing-files block from an explicit (none)

parse_contributing_files documented that callers depend on None vs [], because a
parse failure returning [] would silently disable the check. Only check 8
honoured it; checks 4/5 (skill-audit) and 3/4 (agent-audit) used a truthiness
test, so an unreadable block disabled them without a word.

Two live corpus entries were skipping this way. A sweep of all 32 sources.md
found 134 entries, exactly 2 parsing to None, both in gitea-files: one heading
carried an inline parenthetical that defeated both regexes, and one (none) was
written without its leading bullet. Also pins EMPTY_SOURCE_KEYS_RE to the two
indents parse_source_keys actually reads.

agent-audit had no INFO tier at all, so it gains one rather than reporting a
check that could not run as a FAIL.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EJJrm5YmacbwMdzZpXcoti

plugins/kyberforge/.apm/skills/agent-audit/tests/validate-provenance.bats

@@ -433,3 +433,140 @@ EOF
     run bash "$SCRIPT" "$root/.apm/agents/my-agent.agent.md"
     assert_success
 }
+
+# ---------------------------------------------------------------------------
+# Checks 3 and 4: None ("could not parse") is NOT [] ("explicitly (none)")
+#
+# parse_contributing_files returns three distinguishable answers and checks 3
+# and 4 have to honour all three. `[]` is the author writing "(none)" — the
+# skip is correct and silent. None is a Contributing files block the parser
+# cannot read, and skipping THAT silently disables both checks on the one entry
+# least likely to be right, which is the failure mode the parser's own
+# docstring warns about. The assertions below are therefore about the INFO
+# appearing; a silent exit 0 is exactly the bug.
+# ---------------------------------------------------------------------------
+
+@test "INFO: an unparsable Contributing files block names the slug instead of skipping checks 3 and 4 silently" {
+    local root="$TMPDIR/package"
+    make_package "$root"
+    make_agent_with_source_keys "$root"
+    cat > "$root/sources.md" <<EOF
+# Sources
+
+## my-source
+
+- **URL:** https://example.com/my-source
+- **Description:** A test source.
+- **Research doc:** (none)
+**Contributing files:**
+* .apm/agents/ghost.agent.md (asterisk bullets are not the bullet form)
+- **Status:** \`extracted\`
+EOF
+    run bash "$SCRIPT" "$root/.apm/agents/my-agent.agent.md"
+    assert_success
+    assert_output --partial "INFO"
+    assert_output --partial "Contributing-file checks skipped for 'my-source' — the Contributing files block could not be parsed"
+}
+
+@test "INFO: an entry with no Contributing files field at all is reported, not skipped silently" {
+    local root="$TMPDIR/package"
+    make_package "$root"
+    make_agent_with_source_keys "$root"
+    cat > "$root/sources.md" <<EOF
+# Sources
+
+## my-source
+
+- **URL:** https://example.com/my-source
+- **Description:** A test source.
+- **Research doc:** (none)
+- **Status:** \`extracted\`
+EOF
+    run bash "$SCRIPT" "$root/.apm/agents/my-agent.agent.md"
+    assert_success
+    assert_output --partial "INFO"
+    assert_output --partial "Contributing-file checks skipped for 'my-source' — the Contributing files block could not be parsed"
+}
+
+@test "checks 3 and 4 skipped silently: an explicit '(none)' emits no INFO" {
+    local root="$TMPDIR/package"
+    make_package "$root"
+    make_agent_with_source_keys "$root"
+    make_sources_md "$root" "my-source" "(none — not used directly)"
+    run bash "$SCRIPT" "$root/.apm/agents/my-agent.agent.md"
+    assert_success
+    assert_output ""
+}
+
+@test "checks 3 and 4 still run: a parseable Contributing files list is not diverted to the INFO" {
+    local root="$TMPDIR/package"
+    make_package "$root"
+    make_agent_with_source_keys "$root"
+    make_sources_md "$root" "my-source" ".apm/agents/nonexistent.agent.md"
+    run bash "$SCRIPT" "$root/.apm/agents/my-agent.agent.md"
+    assert_failure
+    assert_output --partial "FAIL"
+    assert_output --partial "Contributing file '.apm/agents/nonexistent.agent.md' does not exist"
+    refute_output --partial "could not be parsed"
+}
+
+# ---------------------------------------------------------------------------
+# The INFO tier itself: kind-aware printing and a kind-aware exit code
+#
+# INFO is new here — before it, findings was a 5-tuple and print_findings
+# stamped every entry FAIL. The two cases below pin the tier rather than any
+# one check: an INFO must print under the INFO prefix and leave the exit code
+# at 0, and a real FAIL must keep printing under the FAIL prefix and still exit
+# non-zero even when an INFO is sitting in the same findings list.
+# ---------------------------------------------------------------------------
+
+@test "INFO tier: an INFO alone prints as INFO with a Note and does not set a failing exit code" {
+    local root="$TMPDIR/package"
+    make_package "$root"
+    make_agent_with_source_keys "$root"
+    cat > "$root/sources.md" <<EOF
+# Sources
+
+## my-source
+
+- **URL:** https://example.com/my-source
+- **Description:** A test source.
+- **Research doc:** (none)
+- **Status:** \`extracted\`
+EOF
+    run bash "$SCRIPT" "$root/.apm/agents/my-agent.agent.md"
+    assert_success
+    assert_output --partial "INFO  Contributing-file checks skipped for 'my-source'"
+    assert_output --partial "Note:"
+    refute_output --partial "FAIL"
+}
+
+@test "FAIL tier: a genuine FAIL alongside an INFO still prints as FAIL and exits non-zero" {
+    local root="$TMPDIR/package"
+    make_package "$root"
+    make_agent_with_source_keys "$root"
+    cat > "$root/sources.md" <<EOF
+# Sources
+
+## my-source
+
+- **URL:** https://example.com/my-source
+- **Description:** A test source.
+- **Contributing files:** .apm/agents/nonexistent.agent.md
+- **Research doc:** (none)
+- **Status:** \`extracted\`
+
+## ghost-source
+
+- **URL:** https://example.com/ghost-source
+- **Description:** Another test source.
+- **Research doc:** (none)
+- **Status:** \`extracted\`
+EOF
+    run bash "$SCRIPT" "$root/.apm/agents/my-agent.agent.md"
+    assert_failure
+    assert_output --partial "FAIL  Contributing file '.apm/agents/nonexistent.agent.md' does not exist"
+    assert_output --partial "Why:"
+    assert_output --partial "INFO  Contributing-file checks skipped for 'ghost-source'"
+    assert_output --partial "Note:"
+}