feat: batch video upscaling with folder upload, directory save, and result comparison (#1051)

* feat: support batch video upscaling with folder upload and directory save

- Add multi-file selection and entire folder upload (webkitdirectory)
- Support drag & drop of both files and folders via FileSystemEntry API
- Add save directory picker using File System Access API (showDirectoryPicker)
- Process videos sequentially with per-file progress and status tracking
- Add right-side result list with click-to-compare functionality
- Add per-video duration and total batch duration display
- Add retry button for failed items with error detail display
- Remove auto-play on comparison viewer load
- Fix worker error handling: handle "error" command to reject stale promises
- Fix event listener accumulation in video comparison (AbortController)
- Fix XSS risk by escaping HTML in all innerHTML injections
- Fix URL revocation timing in download to prevent large file truncation
- Extract writeToSaveDirectory and truncateName helpers to reduce duplication
- Add Usage Guide panel explaining single/multiple/folder upload options

Files changed:
  docs/upscaler/index.html  (+1110/-181)
  docs/upscaler/upscaler.js (+110)

* fix: prevent auto-play and resource consumption during upscaling

- Set preload="metadata" on preview and comparison video elements
- Explicitly pause preview video after setting src in showVideoPreview
- Remove preview video seek sync from batch processing progress callbacks
  (was causing continuous decode during upscaling, wasting GPU resources)
- Remove preview video seek sync from retry progress callback
- All videos now require manual play; no background resource usage

* fix: improve upscaled video quality with higher bitrate and codec support

- Raise base bitrate from 2.5 Mbps (25e5) to 8 Mbps (8e6) for standard and
  firefox processors, preventing quality loss when source videos have high
  bitrates (e.g. 720p @ 16.7 Mbps was producing 1440p @ 10 Mbps, smaller
  than the original file)
- Double the bitrate for mediabunny processor (X.n1 * 2) to account for the
  4x pixel increase from 2x upscaling
- Add H.264 Level 5.1 (avc1.640033) and Level 5.2 (avc1.640034) codecs to
  the fallback lists, since Level 4.0 (avc1.640028, ~24.6 Mbps) cannot
  support the higher bitrates for 1440p+ outputs
- Add latencyMode: "quality" to VideoEncoder configs for both standard and
  firefox processors, prioritizing encoding quality over latency (suitable
  for offline processing)

* feat: add video data comparison panel for original vs upscaled metrics

- Add a comparison data table below the file info bar showing 6 metrics:
  Resolution, File Size, Duration, Est. Bitrate, Pixels, Process Time
- Display per-metric change percentage with color-coded indicators:
  green (↑) for improvements, red (↓) for regressions, gray for neutral
- Estimated bitrate calculated from file size × 8 / video duration
- Table renders after both original and upscaled video metadata loads
- Auto-hide panel on reset

* fix: make video data comparison panel full-width and responsive

- Move comparison data table from inside the left column to the full-width
  area below the left/right layout, so it is no longer constrained by the
  comparison viewer column width
- Remove table-fixed colgroup and overflow-x-auto that caused horizontal
  scrolling on smaller screens
- Table now uses w-full auto-layout, displaying all 4 columns (Metric,
  Original, Upscaled, Change) without requiring horizontal scrolling

---------

Co-authored-by: rionzhao <rionzhao@tencent.com>

assets/js/vs/basic-languages/st/st.js

@@ -0,0 +1,7 @@
+/*!-----------------------------------------------------------------------------
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ * monaco-languages version: 0.30.1(5a7ba61be909ae9e4889768a3453ebb0dec392e2)
+ * Released under the MIT license
+ * https://github.com/Microsoft/monaco-languages/blob/master/LICENSE.md
+ *-----------------------------------------------------------------------------*/
+define("vs/basic-languages/st/st",["require","exports"],(function(e,n){"use strict";Object.defineProperty(n,"__esModule",{value:!0}),n.language=n.conf=void 0,n.conf={comments:{lineComment:"//",blockComment:["(*","*)"]},brackets:[["{","}"],["[","]"],["(",")"],["var","end_var"],["var_input","end_var"],["var_output","end_var"],["var_in_out","end_var"],["var_temp","end_var"],["var_global","end_var"],["var_access","end_var"],["var_external","end_var"],["type","end_type"],["struct","end_struct"],["program","end_program"],["function","end_function"],["function_block","end_function_block"],["action","end_action"],["step","end_step"],["initial_step","end_step"],["transaction","end_transaction"],["configuration","end_configuration"],["tcp","end_tcp"],["recource","end_recource"],["channel","end_channel"],["library","end_library"],["folder","end_folder"],["binaries","end_binaries"],["includes","end_includes"],["sources","end_sources"]],autoClosingPairs:[{open:"[",close:"]"},{open:"{",close:"}"},{open:"(",close:")"},{open:"/*",close:"*/"},{open:"'",close:"'",notIn:["string_sq"]},{open:'"',close:'"',notIn:["string_dq"]},{open:"var_input",close:"end_var"},{open:"var_output",close:"end_var"},{open:"var_in_out",close:"end_var"},{open:"var_temp",close:"end_var"},{open:"var_global",close:"end_var"},{open:"var_access",close:"end_var"},{open:"var_external",close:"end_var"},{open:"type",close:"end_type"},{open:"struct",close:"end_struct"},{open:"program",close:"end_program"},{open:"function",close:"end_function"},{open:"function_block",close:"end_function_block"},{open:"action",close:"end_action"},{open:"step",close:"end_step"},{open:"initial_step",close:"end_step"},{open:"transaction",close:"end_transaction"},{open:"configuration",close:"end_configuration"},{open:"tcp",close:"end_tcp"},{open:"recource",close:"end_recource"},{open:"channel",close:"end_channel"},{open:"library",close:"end_library"},{open:"folder",close:"end_folder"},{open:"binaries",close:"end_binaries"},{open:"includes",close:"end_includes"},{open:"sources",close:"end_sources"}],surroundingPairs:[{open:"{",close:"}"},{open:"[",close:"]"},{open:"(",close:")"},{open:'"',close:'"'},{open:"'",close:"'"},{open:"var",close:"end_var"},{open:"var_input",close:"end_var"},{open:"var_output",close:"end_var"},{open:"var_in_out",close:"end_var"},{open:"var_temp",close:"end_var"},{open:"var_global",close:"end_var"},{open:"var_access",close:"end_var"},{open:"var_external",close:"end_var"},{open:"type",close:"end_type"},{open:"struct",close:"end_struct"},{open:"program",close:"end_program"},{open:"function",close:"end_function"},{open:"function_block",close:"end_function_block"},{open:"action",close:"end_action"},{open:"step",close:"end_step"},{open:"initial_step",close:"end_step"},{open:"transaction",close:"end_transaction"},{open:"configuration",close:"end_configuration"},{open:"tcp",close:"end_tcp"},{open:"recource",close:"end_recource"},{open:"channel",close:"end_channel"},{open:"library",close:"end_library"},{open:"folder",close:"end_folder"},{open:"binaries",close:"end_binaries"},{open:"includes",close:"end_includes"},{open:"sources",close:"end_sources"}],folding:{markers:{start:new RegExp("^\\s*#pragma\\s+region\\b"),end:new RegExp("^\\s*#pragma\\s+endregion\\b")}}},n.language={defaultToken:"",tokenPostfix:".st",ignoreCase:!0,brackets:[{token:"delimiter.curly",open:"{",close:"}"},{token:"delimiter.parenthesis",open:"(",close:")"},{token:"delimiter.square",open:"[",close:"]"}],keywords:["if","end_if","elsif","else","case","of","to","__try","__catch","__finally","do","with","by","while","repeat","end_while","end_repeat","end_case","for","end_for","task","retain","non_retain","constant","with","at","exit","return","interval","priority","address","port","on_channel","then","iec","file","uses","version","packagetype","displayname","copyright","summary","vendor","common_source","from","extends"],constant:["false","true","null"],defineKeywords:["var","var_input","var_output","var_in_out","var_temp","var_global","var_access","var_external","end_var","type","end_type","struct","end_struct","program","end_program","function","end_function","function_block","end_function_block","interface","end_interface","method","end_method","property","end_property","namespace","end_namespace","configuration","end_configuration","tcp","end_tcp","resource","end_resource","channel","end_channel","library","end_library","folder","end_folder","binaries","end_binaries","includes","end_includes","sources","end_sources","action","end_action","step","initial_step","end_step","transaction","end_transaction"],typeKeywords:["int","sint","dint","lint","usint","uint","udint","ulint","real","lreal","time","date","time_of_day","date_and_time","string","bool","byte","word","dword","array","pointer","lword"],operators:["=",">","<",":",":=","<=",">=","<>","&","+","-","*","**","MOD","^","or","and","not","xor","abs","acos","asin","atan","cos","exp","expt","ln","log","sin","sqrt","tan","sel","max","min","limit","muLine truncated