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.

pkg/types/types.go

@@ -93,7 +93,8 @@ type Task struct {
 	ID             int64      `json:"id"`
 	JobID          int64      `json:"job_id"`
 	RunnerID       *int64     `json:"runner_id,omitempty"`
-	Frame          int        `json:"frame"`
+	Frame          int        `json:"frame"`                   // frame start (inclusive) for render tasks
+	FrameEnd       *int       `json:"frame_end,omitempty"`    // frame end (inclusive); nil = single frame
 	TaskType       TaskType   `json:"task_type"`
 	Status         TaskStatus `json:"status"`
 	CurrentStep    string     `json:"current_step,omitempty"`
@@ -138,8 +139,6 @@ type CreateJobRequest struct {
 	UnhideObjects   *bool           `json:"unhide_objects,omitempty"`    // Optional: Enable unhide tweaks for objects/collections
 	EnableExecution *bool           `json:"enable_execution,omitempty"`  // Optional: Enable auto-execution in Blender (adds --enable-autoexec flag, defaults to false)
 	BlenderVersion  *string         `json:"blender_version,omitempty"`   // Optional: Override Blender version (e.g., "4.2" or "4.2.3")
-	PreserveHDR     *bool           `json:"preserve_hdr,omitempty"`      // Optional: Preserve HDR range for EXR encoding (uses HLG with bt709 primaries)
-	PreserveAlpha   *bool           `json:"preserve_alpha,omitempty"`   // Optional: Preserve alpha channel for EXR encoding (requires AV1 or VP9 codec)
 }
 
 // UpdateJobProgressRequest represents a request to update job progress
@@ -234,8 +233,6 @@ type BlendMetadata struct {
 	UnhideObjects     *bool             `json:"unhide_objects,omitempty"`   // Enable unhide tweaks for objects/collections
 	EnableExecution   *bool             `json:"enable_execution,omitempty"` // Enable auto-execution in Blender (adds --enable-autoexec flag, defaults to false)
 	BlenderVersion    string            `json:"blender_version,omitempty"`  // Detected or overridden Blender version (e.g., "4.2" or "4.2.3")
-	PreserveHDR       *bool             `json:"preserve_hdr,omitempty"`     // Preserve HDR range for EXR encoding (uses HLG with bt709 primaries)
-	PreserveAlpha     *bool             `json:"preserve_alpha,omitempty"`  // Preserve alpha channel for EXR encoding (requires AV1 or VP9 codec)
 }
 
 // MissingFilesInfo represents information about missing files/addons