CmdPal: Synchronize fallback title/subtitle format for consistent scoring (#48085)

## Summary

Fixes #46055 — Standardizes built-in fallback title/subtitle format so
scoring is consistent across all action fallbacks.

## Problem

`MainListPage.cs` scores fallback items by fuzzy-matching the query
against both Title and Subtitle, but with different weights:
- `nameScore = FuzzyScore(query, Title)`
- `descriptionScore = (FuzzyScore(query, Subtitle) - 4) / 2`

Fallbacks that embedded the raw query in Title got artificially higher
scores than those using Subtitle. This made ranking unpredictable.

## Fix

All "action" fallbacks now follow a consistent pattern:
- **Title** = static action description (no query text)
- **Subtitle** = raw query string (unquoted)

"Result" fallbacks (that found a specific matched item) are left
unchanged — they correctly show the matched item name in Title.

## Full Fallback Audit (example query: `notepad`)

| Fallback | Title | Subtitle | Status |
|---|---|---|---|
| WebSearch: Search | "Search the web with Edge" | `Search for notepad`
| **Changed** — was `Search for "notepad"` in subtitle |
| WebSearch: Open URL | "Open in Microsoft Edge" | `Open notepad.com` |
**Changed** — was `Open "notepad.com"` in title |
| Shell: Run | "Run" | `notepad` | Unchanged — already correct |
| Calculator | "3" (result) | `1+2` (query) | Unchanged — intentional
exception |
| Indexer: single result | "notepad.exe" | `C:\Windows\notepad.exe` |
Unchanged — result fallback |
| Indexer: multiple results | "File search" | `Search for notepad in
files` | **Changed** — was `Search for "notepad" in files` in title |
| Windows Settings: single | "Notepad settings" | `Settings > Apps` |
Unchanged — result fallback |
| Windows Settings: multiple | "Search Windows settings..." | `Search
for notepad` | **Changed** — was `Search for "notepad" in Windows
settings` in title |
| Remote Desktop: exact match | "MyPC" (connection) | "Connect to MyPC"
| Unchanged — result fallback |
| Remote Desktop: arbitrary host | "Remote Desktop" | `Connect to
notepad-host` | **Changed** — was `Connect to notepad-host` in title |
| TimeDate | "Monday, May 23" (result) | "Current date" | Unchanged —
result fallback |
| System | "Shut down" (result) | "Shuts down the computer" | Unchanged
— result fallback |
| PowerToys | "Color Picker" (static) | "Pick a color..." | Unchanged —
result fallback |

## Changes

- `FallbackExecuteSearchItem.cs` — Subtitle uses raw query instead of
`"Search for \"{query}\""` format
- `FallbackOpenURLItem.cs` — Title shows browser name (was query),
Subtitle shows raw query (was browser)
- `FallbackOpenFileItem.cs` — Multi-result: Title is static display
name, Subtitle is raw query
- `FallbackWindowsSettingsItem.cs` — Multi-result: Title is static
description, Subtitle is raw query
- `FallbackRemoteDesktopItem.cs` — Arbitrary host: Title is static
"Remote Desktop", Subtitle is raw query

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Co-authored-by: root <root@io.bbq>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>