fix(pdftract-tuky): fix color clamping test and verify Phase 3.1 coordinator

Fixes:
- Corrected test_color_device_rgb_clamped expected value from "#ff8080" to "#ff0080"
  (G value -0.5 should clamp to 0.0, not 0.5)
- Fixed lifetime annotation in readability.rs (Cow<str> -> Cow<'_, str>)
- Fixed unused_must_use warning in page_class.rs test

Verification (notes/pdftract-tuky.md):
- All 8 children of Phase 3.1 coordinator are closed
- q/Q 64-level depth limit verified (test_64_nested_q_calls_succeed)
- Td chain accumulation verified (test_td_chain)
- Tm/Td ordering correct per ISO 72-bit spec
- /Rotate normalization implemented in child pdftract-1jlpy
- All 6 color operators tracked (72 graphics_state tests pass)

Closes: pdftract-tuky

crates/pdftract-core/src/graphics_state.rs

@@ -980,7 +980,8 @@ mod tests {
     #[test]
     fn test_color_device_rgb_clamped() {
         let color = Color::DeviceRGB([1.5, -0.5, 0.5]);
-        assert_eq!(color.to_css_hex(), Some("#ff8080".into()));
+        // R: 1.5 -> 1.0 -> ff, G: -0.5 -> 0.0 -> 00, B: 0.5 -> 0.5 -> 80
+        assert_eq!(color.to_css_hex(), Some("#ff0080".into()));
     }
 
     // Tests for matrix operations

crates/pdftract-core/src/layout/readability.rs

@@ -153,7 +153,7 @@ mod tests {
     }
 
     impl ScoredSpan for TestSpan {
-        fn text(&self) -> Cow<str> {
+        fn text(&self) -> Cow<'_, str> {
             Cow::Borrowed(&self.text)
         }
 

crates/pdftract-core/src/page_class.rs

@@ -309,7 +309,7 @@ mod page_classification_tests {
     fn test_page_classification_debug_assert_fires_on_invalid_confidence() {
         // Unit test: debug_assert fires on confidence = 1.5 in dev build
         // This test only runs in debug builds where debug_assert! is active
-        PageClassification::new(PageClass::Vector, 1.5, None);
+        let _ = PageClassification::new(PageClass::Vector, 1.5, None);
     }
 
     #[test]

notes/pdftract-tuky.md

@@ -0,0 +1,78 @@
+# Verification Note: pdftract-tuky (Phase 3.1: Graphics State Machine coordinator)
+
+## Summary
+
+All 8 children of the Phase 3.1 Graphics State Machine coordinator are closed. This coordinator delivers the complete graphics state infrastructure consumed by all other Phase 3 operations.
+
+## Acceptance Criteria Status
+
+### 1. All 8 children closed ✅
+
+All children verified closed:
+- pdftract-1jlpy: Page /Rotate normalization (commit 606e162)
+- pdftract-1os1: q/Q stack with depth limit 64 (closed)
+- pdftract-1vxh: BT/ET text object lifecycle (closed)
+- pdftract-44f6: GraphicsState struct + Color enum (closed)
+- pdftract-4dmp: Text state operators (Tc Tw Tz TL Ts Tr) (closed)
+- pdftract-4ubed: Color operators (rg RG k K cs scn) (closed)
+- pdftract-4x0y: Font binding (Tf) + text positioning operators (Td TD Tm T*) (closed)
+- pdftract-p7yll: CTM operator (cm) (closed)
+
+### 2. q/Q 64 levels deep succeeds; 65th level emits GSTATE_STACK_OVERFLOW ✅
+
+Verified by tests in `src/graphics_state/stack.rs`:
+- `test_64_nested_q_calls_succeed`: Pushes 64 times, all succeed
+- `test_gstate_stack_depth_limit`: 65th push fails and emits diagnostic
+- `test_max_depth_is_64`: Verifies stack limit
+
+### 3. Td chain accumulates correctly ✅
+
+Verified by `test_td_chain` in `src/graphics_state/state.rs`:
+```rust
+// BT 100 200 Td 50 0 Td ET should yield translation (150, 200)
+state.begin_text();
+state.move_text(100.0, 200.0);
+state.move_text(50.0, 0.0);
+// Result: (150, 200) ✅
+```
+
+### 4. Tm followed by Td: Td is relative to previous text_line_matrix ✅
+
+Implementation in `src/graphics_state/state.rs`:
+- `set_text_matrix`: Sets both text_matrix and text_line_matrix
+- `move_text`: Updates text_line_matrix first, then copies to text_matrix
+
+This matches ISO 32000-1 Table 108 specification.
+
+### 5. /Rotate 90 normalization ✅
+
+Child bead pdftract-1jlpy (commit 606e162) implements page rotation normalization. The implementation:
+- Handles /Rotate 0/90/180/270 degrees
+- Applies inverse rotation matrix to all glyph bboxes after content stream execution
+- Emits INVALID_ROTATE diagnostic for illegal rotation values
+
+### 6. Color operators tracked ✅
+
+Verified by tests in `crates/pdftract-core/src/graphics_state.rs`:
+- `test_set_fill_gray`, `test_set_fill_rgb`, `test_set_fill_cmyk`
+- `test_set_stroke_gray`, `test_set_stroke_rgb`, `test_set_stroke_cmyk`
+- `test_color_space_component_count`
+- `test_set_fill_color_space`, `test_set_stroke_color_space`
+- `test_set_fill_color_named_spot`
+
+## Test Results
+
+All 72 graphics_state tests pass:
+```
+Summary [   0.049s] 72 tests run: 72 passed, 2612 skipped
+```
+
+## Changes Made
+
+Fixed one incorrect test expectation in `crates/pdftract-core/src/graphics_state.rs`:
+- `test_color_device_rgb_clamped`: Corrected expected value from "#ff8080" to "#ff0080"
+  (The G value -0.5 should clamp to 0.0, not 0.5)
+
+## Coordinator Status
+
+The Phase 3.1 Graphics State Machine is complete and ready for consumption by Phase 3.2-3.5.