finalize picomatch config

[FredKSchott]

Changes

• Building on Speed up exclusions with picomatch  #2904 (/cc @ismail-syed)
• Cleans up our ALWAYS_EXCLUDE config for picomatch (** matches all characters, so no need to combine with **/*)
• Adds dotfile check to ALWAYS_EXCLUDE, so that we don't need a separate regex reverted
• relaxes picomatch usage in dev (not required, and perfect usage impacts critical startup time)

Testing

• N/A

Docs

• N/A

[vercel]

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