feat: calculate real-time directory size in spotter

[sxyazi]

Follow up to #2683, #2691

An implementation of the feature request: #842, #2649

Closes #842
Closes #2649

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This PR adds directory sizes to the folder spotter, the size is computed dynamically in real time and asynchronously, which means:

• Every time a user clicks <Tab> on a directory, the latest size is calculated.
• For large directories, real-time changes in size are reported to the user, with "(?)" appended at the end to indicate that the calculation is in progress.
• If the user closes the spotter or switches directories with the left/right arrow keys, any ongoing calculations will be canceled to avoid wasting resources.

Also, the computed directory size will be updated to the file list:

• If the user sets linemode = size, the latest size will be shown on the right of the file line.
• If the user sets sort_by = size, the file list will be sorted with the latest sizes (if necessary).

screenshot-002318.mp4

[Copilot]

Pull Request Overview

This PR implements a real-time directory size calculation feature in the spotter, including dynamic updates and cancellation of ongoing calculations.

• Integrates asynchronous size calculation and cancellation in the spotter workflow.
• Extends data structures and bindings to support a new Urn type with serialization and error handling.
• Updates related files (FilesOp, update_spotted, and update_size) to incorporate the new functionality.

Reviewed Changes

Copilot reviewed 16 out of 18 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
yazi-shared/src/url/urn.rs	Added Serialize derive to UrnBuf for better integration.
yazi-shared/src/event/data.rs	Updated Data and DataKey enums to include the new Urn variant.
yazi-plugin/src/utils/spot.rs	Added a new id field to SpotLock and updated conversion logic.
yazi-plugin/src/isolate/spot.rs	Introduced a static Ids generator for job creation.
yazi-plugin/src/fs/op.rs	Added support for a new "size" FilesOp using Urn as a key.
yazi-fs/src/files.rs	Modified update_size with filtering logic using a threshold.
yazi-dds/src/sendable.rs	Extended Sendable conversions to include Urn support.
yazi-core/src/tab/commands/update_spotted.rs	Updated spotted handling to use new reset logic.
yazi-core/src/spot/spot.rs	Added a reset method that aborts ongoing tasks and updates UI.
yazi-core/src/spot/commands/close.rs	Simplified close command by invoking the new reset method.
yazi-core/src/mgr/commands/update_mimes.rs	Minor improvements in error handling while parsing options.
yazi-binding/src/urn.rs	Introduced a new Urn binding with FromLua and UserData trait.
yazi-binding/src/url.rs	Modified Url struct & caching to support the new Urn field.
yazi-binding/src/lib.rs	Updated module inclusion to add the Urn module.

Files not reviewed (2)

• yazi-plugin/preset/plugins/folder.lua: Language not supported
• yazi-plugin/preset/ya.lua: Language not supported