Complete cmdpal migration for translator workflows, settings, and result actions

[Copilot]

This continues the partial migration of PowerTranslator onto the new cmdpal extension model. The cmdpal implementation previously covered only the core translation path; this change ports the remaining user-facing behaviors from the legacy PowerToys Run plugin.

• CmdPal feature parity

  • Restores legacy query flows in the cmdpal page:
    • clipboard bootstrap when the query is empty
    • h for translation history
    • l for supported language codes
    • optional second-language result
    • optional raw-query echo
  • Preserves delayed refresh behavior for interactive search.

• Settings migration

  • Adds a cmdpal settings surface for the migrated behaviors:
    • default target language
    • suggestions
    • auto-read
    • second target language
    • dictionary jump
    • system proxy usage
    • code-mode identifier splitting
  • Wires settings changes back into runtime behavior.

• Translation pipeline

  • Expands the cmdpal translation helper from a single-engine path to a fallback chain across:
    • Youdao V2
    • legacy Youdao web API
    • DeepL web API
    • Youdao backup API
  • Keeps alias/language normalization and code-mode preprocessing in the cmdpal path.

• Supporting runtime helpers

  • Ports history tracking and suggestion fetching into the cmdpal extension.
  • Adds richer result metadata so cmdpal items can carry copy targets, descriptions, and search text.

• Result actions

  • Extends cmdpal result items with context actions for:
    • copying subtitle text
    • read-aloud
    • opening the configured dictionary target
  • Improves details rendering for translated results and auxiliary entries.

• Project hygiene

  • Updates the cmdpal README to reflect the newly migrated capabilities.
  • Ignores generated .mono/ artifacts to keep the tree clean.

Example of restored cmdpal query behavior:

hello
hello -> ja
h
l

These now map to the migrated cmdpal flows for translation, explicit target language, history, and language lookup respectively.