Fix Timing Clocks Divergence

Fixed the timing clock divergence between
[tweening.rs](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/tweening.rs)
and
[drawing.rs](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/drawing.rs)
by delegating animation progress evaluation exclusively to
`TweenController`.

`current_time()` in `tweening.rs` was using a monotonic `Instant` epoch
(to support headless execution and unit tests without panicking on
missing Macroquad context), while `drawing.rs` was measuring progress
via `macroquad::time::get_time() - tween.start_time`. Because these two
clocks operate on completely different epochs, subtracting them caused
negative elapsed times, premature clamping, jitter, or animation lockup.

In
[`turtle-lib/src/tweening.rs`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/tweening.rs):
- Added `pub(crate) progress: f32` to
  [`CommandTween`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/tweening.rs#L55-L68)
  to track the current evaluated, eased progress in `[0.0, 1.0]`.
- Made `start_time: f64` and `duration: f64` private to `tweening.rs` so
  outside modules cannot accidentally perform desynchronized clock
  arithmetic.
- Initialized `progress: 0.0` when constructing a new `CommandTween`.
- In `TweenController::update`, evaluated and clamped `tween.progress =
  tween.heading_tweener.move_to(elapsed).clamp(0.0, 1.0)`.

In
[`turtle-lib/src/drawing.rs`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/drawing.rs):
- Removed `use tween::CubicInOut;` and duplicate easing calculations.
- Replaced `get_time() - tween.start_time` and `CubicInOut.tween(...)`
  in in-flight fill preview with `tween.progress`.
- Replaced `get_time() - tween.start_time` and `CubicInOut.tween(...)`
  in `draw_tween_arc` with `tween.progress`.
- Ensured `drawing.rs` has zero clock queries and strictly renders the
  state provided by `TweenController`.

In
[`turtle-lib/src/tweening.rs`](file:///home/dietrich/Projekte/Source/turtlers/turtle-lib/src/tweening.rs#L540-L579):
- Updated `test_animated_mode_pops_to_current_tween` to assert that
  `progress` initializes to `0.0`.
- Added `test_animated_mode_progress_advances_and_clamps` to verify that
  `progress` advances monotonically across frames and stays within
  `[0.0, 1.0]`.

---

```bash
cargo test --package turtle-lib --features svg
```
Output:
```text
running 17 tests
test circle_geometry::tests::test_circle_left_geometry ... ok
test circle_geometry::tests::test_circle_right_geometry ... ok
test command_behavior::tests::test_goto_duration_cartesian_inversion ...
ok
test
command_behavior::tests::test_set_heading_degrees_and_instant_duration
... ok
test execution::tests::test_forward_left_forward ... ok
test general::angle::tests::degrees_to_radians_roundtrip ... ok
test general::angle::tests::from_f64 ... ok
test general::angle::tests::from_integer ... ok
test general::angle::tests::negation ... ok
test general::fontsize::tests::font_size_conversions ... ok
test general::length::tests::test_length_conversions_and_negation ... ok
test general::tests::animation_speed_conversions ... ok
test tweening::tests::test_animated_mode_pops_to_current_tween ... ok
test tweening::tests::test_instant_mode_drains_queue ... ok
test
tweening::tests::test_instant_mode_respects_batch_limit_and_retains_pending
... ok
test tweening::tests::test_streaming_append_commands_does_not_accumulate
... ok
test tweening::tests::test_animated_mode_progress_advances_and_clamps
... ok

test result: ok. 17 passed; 0 failed; 0 ignored; 0 measured; 0 filtered
out; finished in 0.02s

Doc-tests turtle_lib: 34 passed; 0 failed; 1 ignored; 0 measured; 0
filtered out; finished in 0.26s
```

```bash
cargo clippy --package turtle-lib --features svg -- -Wclippy::pedantic \
-Aclippy::cast_precision_loss -Aclippy::cast_sign_loss
-Aclippy::cast_possible_truncation
```
Output:
```text
Finished `dev` profile [optimized + debuginfo] target(s) in 0.82s
```
**0 warnings.**

```bash
cargo run --example yinyang --features svg -- --export-svg
/tmp/yinyang_test.svg
```
Output:
```text
SVG exported successfully to: /tmp/yinyang_test.svg
```

```bash
cargo build --package turtle-lib --examples
```
Output:
```text
Finished `dev` profile [optimized + debuginfo] target(s) in 6.74s
```
**All 30 examples compiled cleanly with 0 errors and 0 warnings.**

turtle-lib-macros/Cargo.toml

@@ -10,4 +10,4 @@ proc-macro = true
 [dependencies]
 proc-macro2 = "1.0"
 quote = "1.0"
-syn = { version = "2.0", features = ["full"] }
+syn = { version = "3.0", features = ["full"] }