refactor: massive codebase restructuring — naming, splitting, DRY

Crate renames:
  - zesdex-entities::seaorm → domain (misleading name, no SeaORM used)
  - zesdex-dto → merged into zesdex-entities (100% re-exports)
  - zesdex-libs → zesdex-infra (vague name)

Module renames:
  - app/harness → guard (misleading: safety gatekeeper, not test harness)
  - runtime/commands → action_dispatch (name clashed with controller/command)
  - resources → prompts (embedded prompt text, not general resources)
  - tool/seqthink → sequential_think (unreadable abbreviation)
  - msglog/query → insert (module only inserts, never queries)

Dead code removal:
  - app/mode/help.rs (orphaned — not declared in mod.rs)
  - app/mode/loading.rs (orphaned — not declared in mod.rs)

File splitting (71 new files, avg ~115 lines/file):
  - app/runtime/actions/: 1→8 files (was 2030 lines)
  - view/overlays/: 1→16 files (was 1167 lines)
  - tool/lsp/: 1→8 per-tool files (was 909 lines)
  - main.rs: 1→5 files (session, daemon, attach, event_loop)
  - workflow/engine + hive_mind: 2→10 files
  - subagent/engine + auto: 2→9 files
  - lsp/provisioner: 1→5 files
  - review/: 1→6 files
  - guard/: 1→2 files (extracted patterns)
  - state/misc: 1→3 files (input, scroll)
  - mcp/: 1→3 files (transport, adapter)
  - stream/json_repair extracted from turn.rs

DRY:
  - Pattern constants (STUB_PATTERNS etc) in guard/patterns shared with subagent
  - 3 near-identical background spawners → 1 generic + thin wrappers
  - Shared spawn_subagent_with_drain() extracted
  - Shared create_session() in main
  - write_osc52 deduplicated

Bug fixes:
  - archive_message(): sess.db → db (wrong variable name)
  - execute_one_tool(): wrong parameter name
  - check_credential_read() function was missing (restored from test expectations)

crates/zesdex-backend/src/app/subagent/auto/paths.rs

@@ -0,0 +1,124 @@
+//! Path classification helpers for auto-subagent orchestration.
+//!
+//! Determines whether a file path is reviewable and whether it represents
+//! production code (vs. tests, config, or documentation) — used to decide
+//! which background subagents should fire for a given set of modified files.
+
+/// File extensions that should not trigger auto-review (config, lock, data).
+pub(crate) const SKIP_REVIEW_EXTENSIONS: &[&str] = &[
+    ".lock",
+    ".md",
+    ".txt",
+    ".json",
+    ".toml",
+    ".yaml",
+    ".yml",
+    ".svg",
+    ".png",
+    ".jpg",
+    ".ico",
+    ".woff",
+    ".woff2",
+];
+
+/// File names that should not trigger auto-review.
+pub(crate) const SKIP_REVIEW_FILES: &[&str] = &[
+    "Cargo.lock",
+    "yarn.lock",
+    "package-lock.json",
+    ".gitignore",
+    ".env",
+    ".env.example",
+];
+
+/// Check whether a file path is worth auto-reviewing (not config/lock/data).
+///
+/// Vendored/generated directories are matched by path *segment* rather than
+/// a `/target/`-style substring check — the substring form misses paths
+/// where the directory is the first component (e.g. `target/debug/build.rs`,
+/// which has no leading slash), the same class of bug fixed in
+/// `is_production_code` below.
+pub fn is_reviewable_path(path: &str) -> bool {
+    let lower = path.to_lowercase();
+    if SKIP_REVIEW_FILES.iter().any(|f| lower.ends_with(f)) {
+        return false;
+    }
+    if SKIP_REVIEW_EXTENSIONS.iter().any(|e| lower.ends_with(e)) {
+        return false;
+    }
+    // Skip paths that are clearly generated or vendored
+    let in_vendored_dir = std::path::Path::new(&lower).components().any(|c| {
+        matches!(
+            c,
+            std::path::Component::Normal(seg)
+                if matches!(seg.to_str(), Some("target" | "node_modules" | ".git" | "vendor"))
+        )
+    });
+    if in_vendored_dir {
+        return false;
+    }
+    true
+}
+
+/// Determine whether a file change looks like it modifies production logic
+/// (vs. tests, config, or documentation) — used to decide if a test-gen
+/// or security-review background subagent should fire.
+///
+/// Matches test-ness by path *segment* (a directory literally named
+/// "test"/"tests"/"__tests__") or by filename convention
+/// (`foo_test.rs`, `foo.test.ts`, `test_foo.py`, `foo_spec.rb`), not by a
+/// raw substring check — a plain `.contains("test")` would wrongly exclude
+/// legitimate production files like `src/attestation.rs` or
+/// `src/latest/foo.rs`.
+pub(crate) fn is_production_code(path: &str) -> bool {
+    let lower = path.to_lowercase();
+    let path_obj = std::path::Path::new(&lower);
+
+    let in_test_dir = path_obj.components().any(|c| {
+        matches!(
+            c,
+            std::path::Component::Normal(seg)
+                if matches!(seg.to_str(), Some("test" | "tests" | "__tests__"))
+        )
+    });
+
+    let file_stem = path_obj.file_stem().and_then(|s| s.to_str()).unwrap_or("");
+    let is_test_filename = file_stem.starts_with("test_")
+        || file_stem.ends_with("_test")
+        || std::path::Path::new(file_stem)
+            .extension()
+            .is_some_and(|ext| ext.eq_ignore_ascii_case("test"))
+        || file_stem == "spec"
+        || file_stem.ends_with("_spec")
+        || std::path::Path::new(file_stem)
+            .extension()
+            .is_some_and(|ext| ext.eq_ignore_ascii_case("spec"));
+
+    if in_test_dir || is_test_filename {
+        return false;
+    }
+
+    // Only source files — use Path::extension() to avoid clippy
+    // case_sensitive_file_extension_comparisons lint
+    path_obj
+        .extension()
+        .and_then(|ext| ext.to_str())
+        .is_some_and(|ext| {
+            matches!(
+                ext,
+                "rs" | "ts"
+                    | "tsx"
+                    | "js"
+                    | "jsx"
+                    | "go"
+                    | "py"
+                    | "java"
+                    | "kt"
+                    | "swift"
+                    | "c"
+                    | "cpp"
+                    | "h"
+                    | "hpp"
+            )
+        })
+}