chore: workspace-wide cleanup — clippy::pedantic baseline + auto-fix

cut PR v0.18.0 전 마지막 정리. 사용자 요청: "전체 코드베이스를 깔끔하고 알아보기 쉽게".

## Workspace lints

- `Cargo.toml` 의 `[workspace.lints.clippy]` 에 `pedantic = "warn"` (priority -1) + 의도적 allow-list 추가:
  - cast_possible_truncation / cast_possible_wrap / cast_sign_loss / cast_precision_loss — ONNX i64 / hash modular reduction 등 의도적 truncation.
  - doc_markdown / missing_errors_doc / missing_panics_doc — cosmetic doc style.
  - too_many_lines / module_name_repetitions / must_use_candidate / needless_pass_by_value / manual_let_else / items_after_statements / similar_names — informational only.
  - format_collect / match_wildcard_for_single_variants / trivially_copy_pass_by_ref / unnecessary_wraps — intentional patterns (exhaustive match, future Result variants 등).
  - default_trait_access — `Foo::default()` 가 idiomatic.
  - float_cmp — NLI / RRF score 의 explicit threshold 비교 의도.
  - struct_excessive_bools / case_sensitive_file_extension_comparisons / naive_bytecount / ignore_without_reason — domain-specific 의도.
  - format_push_string / return_self_not_must_use / match_same_arms — builder / wire-label / hot-path 패턴 보존.
  - needless_continue / used_underscore_binding / nonminimal_bool / unreadable_literal / many_single_char_names / doc_link_with_quotes / assigning_clones / collapsible_str_replace / trivial_regex / elidable_lifetime_names / range_plus_one / explicit_iter_loop / implicit_hasher / ref_option — remaining low-value style.
- 각 24 crate `Cargo.toml` 에 `[lints] workspace = true` 추가.

## Auto-fix

`cargo clippy --workspace --all-targets --fix` 적용 — 128 files changed, 552 insertions / 472 deletions. 주로:
- uninlined_format_args (~18): `format!("{}", x)` → `format!("{x}")`.
- redundant_closure_for_method_calls (~33): `.map(|x| x.foo())` → `.map(T::foo)`.
- 그 외 mechanical refactor.

## 검증

- `cargo clippy --workspace --all-targets -j 1 -- -D warnings` clean (pedantic + 모든 lint group).
- `cargo test --workspace --no-fail-fast -j 1` — **1293 tests pass + 1 pre-existing flaky fail** (`kebab-mcp::tools_call_ask_multi_hop::ask_tool_routes_multi_hop_true_to_decompose_first`, HOTFIX candidate, cleanup 무관). 회귀 0.

Wire 영향: 없음.
Behavior 영향: 없음 (mechanical refactor only).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/kebab-cli/tests/cli_ingest_file.rs

@@ -88,5 +88,5 @@ max_context_tokens = 8000
     let stdout = String::from_utf8_lossy(&out.stdout);
     let v: serde_json::Value = serde_json::from_str(stdout.trim()).unwrap();
     assert_eq!(v.get("schema_version").and_then(|s| s.as_str()), Some("ingest_report.v1"));
-    assert_eq!(v.get("new").and_then(|n| n.as_u64()), Some(1));
+    assert_eq!(v.get("new").and_then(serde_json::Value::as_u64), Some(1));
 }

crates/kebab-cli/tests/cli_ingest_stdin.rs

@@ -96,5 +96,5 @@ max_context_tokens = 8000
     let stdout = String::from_utf8_lossy(&out.stdout);
     let v: serde_json::Value = serde_json::from_str(stdout.trim()).unwrap();
     assert_eq!(v.get("schema_version").and_then(|s| s.as_str()), Some("ingest_report.v1"));
-    assert_eq!(v.get("new").and_then(|n| n.as_u64()), Some(1));
+    assert_eq!(v.get("new").and_then(serde_json::Value::as_u64), Some(1));
 }

crates/kebab-cli/tests/cli_mcp_smoke.rs

@@ -43,7 +43,7 @@ fn cli_mcp_initialize_then_tools_list() {
     reader.read_line(&mut line).unwrap();
     let init: serde_json::Value = serde_json::from_str(line.trim()).unwrap();
     assert_eq!(
-        init.get("id").and_then(|i| i.as_i64()),
+        init.get("id").and_then(serde_json::Value::as_i64),
         Some(1),
         "unexpected id in initialize response: {init}"
     );
@@ -57,7 +57,7 @@ fn cli_mcp_initialize_then_tools_list() {
     reader.read_line(&mut line).unwrap();
     let list: serde_json::Value = serde_json::from_str(line.trim()).unwrap();
     assert_eq!(
-        list.get("id").and_then(|i| i.as_i64()),
+        list.get("id").and_then(serde_json::Value::as_i64),
         Some(2),
         "unexpected id in tools/list response: {list}"
     );

crates/kebab-cli/tests/cli_schema.rs

@@ -76,8 +76,7 @@ fn cli_schema_json_emits_schema_v1() {
     assert!(
         v.get("kebab_version")
             .and_then(|s| s.as_str())
-            .map(|s| !s.is_empty())
-            .unwrap_or(false),
+            .is_some_and(|s| !s.is_empty()),
         "kebab_version must be a non-empty string"
     );
 
@@ -86,12 +85,12 @@ fn cli_schema_json_emits_schema_v1() {
         .and_then(|c| c.as_object())
         .expect("capabilities must be a JSON object");
     assert_eq!(
-        caps.get("json_mode").and_then(|b| b.as_bool()),
+        caps.get("json_mode").and_then(serde_json::Value::as_bool),
         Some(true),
         "capabilities.json_mode must be true"
     );
     assert_eq!(
-        caps.get("mcp_server").and_then(|b| b.as_bool()),
+        caps.get("mcp_server").and_then(serde_json::Value::as_bool),
         Some(true),
         "capabilities.mcp_server must be true (fb-30)"
     );

crates/kebab-cli/tests/ingest_progress_cli.rs

@@ -155,8 +155,8 @@ fn ingest_json_progress_lines_carry_kind_and_ts() {
             saw_completed = true;
             // Counts mirror the report.
             let counts = v.get("counts").unwrap();
-            assert_eq!(counts.get("scanned").and_then(|n| n.as_u64()), Some(2));
-            assert_eq!(counts.get("new").and_then(|n| n.as_u64()), Some(2));
+            assert_eq!(counts.get("scanned").and_then(serde_json::Value::as_u64), Some(2));
+            assert_eq!(counts.get("new").and_then(serde_json::Value::as_u64), Some(2));
         }
     }
     assert!(saw_scan_started, "missing scan_started event");