trace: add execution route visibility + debug passthrough; phase2170 canaries; docs

- Add HAKO_TRACE_EXECUTION to trace executor route
  - Rust hv1_inline: stderr [trace] executor: hv1_inline (rust)
  - Hakovm dispatcher: stdout [trace] executor: hakovm (hako)
  - test_runner: trace lines for hv1_inline/core/hakovm routes
- Add HAKO_VERIFY_SHOW_LOGS and HAKO_DEBUG=1 (enables both)
  - verify_v1_inline_file() log passthrough with numeric rc extraction
  - test_runner exports via HAKO_DEBUG
- Canary expansion under phase2170 (state spec)
  - Array: push×5/10 → size, len/length alias, per‑recv/global, flow across blocks
  - Map: set dup-key non-increment, value_state get/has
  - run_all.sh: unify, remove SKIPs; all PASS
- Docs
  - ENV_VARS.md: add Debug/Tracing toggles and examples
  - PLAN.md/CURRENT_TASK.md: mark 21.7 green, add Quickstart lines

All changes gated by env vars; default behavior unchanged.

src/boxes/file/mod.rs

@@ -84,8 +84,17 @@ impl FileBox {
     }
 
     pub fn write_all(&self, _buf: &[u8]) -> Result<(), String> {
-        // CoreRo does not support write - Fail-Fast
-        Err("Write operation not supported in read-only mode".to_string())
+        // Fail-Fast by capability: consult provider caps
+        let caps = self.provider
+            .as_ref()
+            .map(|p| p.caps())
+            .or_else(|| provider_lock::get_filebox_caps())
+            .unwrap_or_else(|| provider::FileCaps::read_only());
+        if !caps.write {
+            return Err("Write unsupported by current FileBox provider (read-only)".to_string());
+        }
+        // Write-capable provider not wired yet
+        Err("Write supported by provider but not implemented in this build".to_string())
     }
 
     /// ファイルの内容を読み取る
@@ -98,8 +107,15 @@ impl FileBox {
 
     /// ファイルに内容を書き込む
     pub fn write(&self, _content: Box<dyn NyashBox>) -> Box<dyn NyashBox> {
-        // Fail-Fast: CoreRo does not support write
-        Box::new(StringBox::new("Error: Write operation not supported in read-only mode"))
+        let caps = self.provider
+            .as_ref()
+            .map(|p| p.caps())
+            .or_else(|| provider_lock::get_filebox_caps())
+            .unwrap_or_else(|| provider::FileCaps::read_only());
+        if !caps.write {
+            return Box::new(StringBox::new("Error: write unsupported by provider (read-only)"));
+        }
+        Box::new(StringBox::new("Error: write supported but not implemented in this build"))
     }
 
     /// ファイルが存在するかチェック
@@ -110,14 +126,28 @@ impl FileBox {
 
     /// ファイルを削除
     pub fn delete(&self) -> Box<dyn NyashBox> {
-        // Fail-Fast: CoreRo does not support delete
-        Box::new(StringBox::new("Error: Delete operation not supported in read-only mode"))
+        let caps = self.provider
+            .as_ref()
+            .map(|p| p.caps())
+            .or_else(|| provider_lock::get_filebox_caps())
+            .unwrap_or_else(|| provider::FileCaps::read_only());
+        if !caps.write {
+            return Box::new(StringBox::new("Error: delete unsupported by provider (read-only)"));
+        }
+        Box::new(StringBox::new("Error: delete supported but not implemented in this build"))
     }
 
     /// ファイルをコピー
     pub fn copy(&self, _dest: &str) -> Box<dyn NyashBox> {
-        // Fail-Fast: CoreRo does not support copy
-        Box::new(StringBox::new("Error: Copy operation not supported in read-only mode"))
+        let caps = self.provider
+            .as_ref()
+            .map(|p| p.caps())
+            .or_else(|| provider_lock::get_filebox_caps())
+            .unwrap_or_else(|| provider::FileCaps::read_only());
+        if !caps.write {
+            return Box::new(StringBox::new("Error: copy unsupported by provider (read-only)"));
+        }
+        Box::new(StringBox::new("Error: copy supported but not implemented in this build"))
     }
 }