feat: Enhance Gantt charts with sequence names, adaptive ticks, and sorting

Improvements to seq_compiler Gantt chart visualization:

- Add optional sequence name support: SEQUENCE <start> <pri> ["name"] [end]
  Names displayed in both ASCII and HTML Gantt charts for better readability

- Implement adaptive tick intervals based on demo duration:
  * ≤5s: 1s intervals
  * ≤40s: 2s intervals (fixes 32.5s demo from 5s to 2s)
  * ≤100s: 5s intervals
  * >100s: 10s+ intervals

- Sort sequences by start time in Gantt output for chronological visualization

- Add horizontal visual separators between sequences in both ASCII and HTML

- Update documentation (SEQUENCE.md) and quick reference (demo.seq)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

1 files changed, 12 insertions, 1 deletions

diff --git a/doc/SEQUENCE.md b/doc/SEQUENCE.md
index 614339e..7aa951d 100644
--- a/doc/SEQUENCE.md
+++ b/doc/SEQUENCE.md
@@ -63,7 +63,7 @@ Specifies when the demo should automatically exit (optional).
 
 ### SEQUENCE Declaration
 ```
-SEQUENCE <global_start> <priority> [optional_end]
+SEQUENCE <global_start> <priority> ["optional_name"] [optional_end]
   EFFECT <EffectClassName> <local_start> <local_end> <priority> [constructor_args...]
 ```
 
@@ -72,11 +72,22 @@ SEQUENCE <global_start> <priority> [optional_end]
 - `priority`: Render order between sequences (higher = rendered later/on top)
   - Use 0-9 for scene effects
   - Use 10+ for post-processing
+- `"optional_name"`: Optional human-readable name in quotes (e.g., `"Opening Scene"`)
+  - If specified, the name will be displayed in Gantt charts for better readability
+  - Helps identify sequences when visualizing complex timelines
 - `[optional_end]`: Optional end time in brackets (e.g., `[30.0]`)
   - If specified, all effects in the sequence will be forcefully ended at this time
   - Time is relative to the sequence start
   - If omitted, effects run until their individual end times
 
+**Examples:**
+```
+SEQUENCE 0 0                        # Basic sequence (no name, no explicit end)
+SEQUENCE 0 0 "Intro"                # Named sequence
+SEQUENCE 0 0 [5.0]                  # Sequence with explicit end time
+SEQUENCE 0 0 "Action Scene" [10.0]  # Named sequence with explicit end time
+```
+
 ### EFFECT Declaration
 ```
 EFFECT <+|=|-> <EffectClassName> <local_start> <local_end> [constructor_args...]