Refactor web build process and update documentation

- Removed Node.js build artifacts from .gitignore and adjusted Makefile to reflect changes in web UI build process, now using server-rendered Go templates instead of React.
- Updated README to clarify the new web UI architecture and output formats, emphasizing the removal of the Node.js build step.
- Added a command to set the number of frames per render task in manager configuration, enhancing user control over rendering settings.
- Improved Gitea workflow by removing unnecessary npm install step, streamlining the CI process.

internal/runner/tasks/processor.go

@@ -2,12 +2,17 @@
 package tasks
 
 import (
+	"errors"
+	"fmt"
 	"jiggablend/internal/runner/api"
 	"jiggablend/internal/runner/blender"
 	"jiggablend/internal/runner/encoding"
 	"jiggablend/internal/runner/workspace"
 	"jiggablend/pkg/executils"
 	"jiggablend/pkg/types"
+	"os/exec"
+	"sync"
+	"time"
 )
 
 // Processor handles a specific task type.
@@ -20,7 +25,8 @@ type Context struct {
 	TaskID   int64
 	JobID    int64
 	JobName  string
-	Frame    int
+	Frame    int // frame start (inclusive); kept for backward compat
+	FrameEnd int // frame end (inclusive); same as Frame for single-frame
 	TaskType string
 	WorkDir  string
 	JobToken string
@@ -34,11 +40,14 @@ type Context struct {
 	Processes *executils.ProcessTracker
 }
 
-// NewContext creates a new task context.
+// ErrJobCancelled indicates the manager-side job was cancelled during execution.
+var ErrJobCancelled = errors.New("job cancelled")
+
+// NewContext creates a new task context. frameEnd should be >= frame; if 0 or less than frame, it is treated as single-frame (frameEnd = frame).
 func NewContext(
 	taskID, jobID int64,
 	jobName string,
-	frame int,
+	frameStart, frameEnd int,
 	taskType string,
 	workDir string,
 	jobToken string,
@@ -50,11 +59,15 @@ func NewContext(
 	encoder *encoding.Selector,
 	processes *executils.ProcessTracker,
 ) *Context {
+	if frameEnd < frameStart {
+		frameEnd = frameStart
+	}
 	return &Context{
 		TaskID:    taskID,
 		JobID:     jobID,
 		JobName:   jobName,
-		Frame:     frame,
+		Frame:     frameStart,
+		FrameEnd:  frameEnd,
 		TaskType:  taskType,
 		WorkDir:   workDir,
 		JobToken:  jobToken,
@@ -145,12 +158,65 @@ func (c *Context) ShouldEnableExecution() bool {
 	return c.Metadata != nil && c.Metadata.EnableExecution != nil && *c.Metadata.EnableExecution
 }
 
-// ShouldPreserveHDR returns whether to preserve HDR range for EXR encoding.
-func (c *Context) ShouldPreserveHDR() bool {
-	return c.Metadata != nil && c.Metadata.PreserveHDR != nil && *c.Metadata.PreserveHDR
+// IsJobCancelled checks whether the manager marked this job as cancelled.
+func (c *Context) IsJobCancelled() (bool, error) {
+	if c.Manager == nil {
+		return false, nil
+	}
+	status, err := c.Manager.GetJobStatus(c.JobID)
+	if err != nil {
+		return false, err
+	}
+	return status == types.JobStatusCancelled, nil
 }
 
-// ShouldPreserveAlpha returns whether to preserve alpha channel for EXR encoding.
-func (c *Context) ShouldPreserveAlpha() bool {
-	return c.Metadata != nil && c.Metadata.PreserveAlpha != nil && *c.Metadata.PreserveAlpha
+// CheckCancelled returns ErrJobCancelled if the job was cancelled.
+func (c *Context) CheckCancelled() error {
+	cancelled, err := c.IsJobCancelled()
+	if err != nil {
+		return fmt.Errorf("failed to check job status: %w", err)
+	}
+	if cancelled {
+		return ErrJobCancelled
+	}
+	return nil
+}
+
+// StartCancellationMonitor polls manager status and kills cmd if job is cancelled.
+// Caller must invoke returned stop function when cmd exits.
+func (c *Context) StartCancellationMonitor(cmd *exec.Cmd, taskLabel string) func() {
+	stop := make(chan struct{})
+	var once sync.Once
+
+	go func() {
+		ticker := time.NewTicker(2 * time.Second)
+		defer ticker.Stop()
+
+		for {
+			select {
+			case <-stop:
+				return
+			case <-ticker.C:
+				cancelled, err := c.IsJobCancelled()
+				if err != nil {
+					c.Warn(fmt.Sprintf("Could not check cancellation for %s task: %v", taskLabel, err))
+					continue
+				}
+				if !cancelled {
+					continue
+				}
+				c.Warn(fmt.Sprintf("Job %d was cancelled, stopping %s task early", c.JobID, taskLabel))
+				if cmd != nil && cmd.Process != nil {
+					_ = cmd.Process.Kill()
+				}
+				return
+			}
+		}
+	}()
+
+	return func() {
+		once.Do(func() {
+			close(stop)
+		})
+	}
 }