Add a hotkey for commenting out the current line or lines on the /play page

[OpenGLShaders]

Changelog category (leave one):

• Improvement

Changelog entry (a user-readable short description of the changes that goes into CHANGELOG.md):

• You can now quickly comment or uncomment your currently selected lines in the Web UI query editor using Ctrl+/ (or Cmd+/ on Mac), making it easier to temporarily disable parts of your query while testing.

[CLAassistant]

All committers have signed the CLA.

[clickhouse-gh]

Workflow [PR], commit [2cac495]

Summary: ❌

job_name	test_name	status	info	comment
Integration tests (amd_asan, db disk, old analyzer, 1/6)		failure
	test_filesystem_cache/test.py::test_caches_with_the_same_configuration[node]	FAIL	cidb
AST fuzzer (arm_asan)		failure
	Logical error: 'Invalid number of rows in Chunk Nullable(size = 0, Int32(size = 0), UInt8(size = 0)) UInt16(size = 2) UInt8(size = 2) UInt32(size = 2) Int8(size = 2) Int16(size = 2) Int32(size = 2) LowCardinality(size = 2, UInt8(size = 2), Unique(size = 3, Float32(size = 3))) Float64(size = 2) Decimal32(size = 2) Decimal64(size = 2) column Nullable(Int32) at position 0: expected 2, got 0'	FAIL	cidb
AST fuzzer (amd_tsan)		failure
	Logical error: 'col.name == prewhere_info->prewhere_column_name'	FAIL	cidb
BuzzHouse (amd_debug)		failure
	Logical error: 'Inconsistent AST formatting: the query:	FAIL	cidb
Performance Comparison (amd_release, master_head, 4/6)		failure
	Check Results	failure

[OpenGLShaders]

@Fgrtue thanks for moving this to the test stage - anything I need to do to get the test failures above resolved? They seem unrelated to my change (from what I can tell at least...)

[Copilot]

Pull request overview

This PR adds keyboard shortcut support for commenting and uncommenting code in the Web UI query editor. Users can now press Ctrl+/ (or Cmd+/ on Mac) to toggle SQL comments on selected lines.

Key Changes:

• Implements a new keyboard event handler for Ctrl+/ or Cmd+/ that comments/uncomments the currently selected line(s)
• Uses SQL comment syntax (--) with intelligent handling of already-commented lines
• Preserves user selection after the operation for easy workflow

[Fgrtue]

Hi @OpenGLShaders! Thank you for your contribution.
Yes, the failing tests seem to be unrelated.
Next, please wait until the changed are reviewed.