Always left-align status text in pretty tables

[Copilot]

The pretty-table layout left-padded plain status values to align under the text of symbol-prefixed values (e.g. ⟳ Update available). This special-casing is removed; status text is now always left-aligned.

Changes

• pkg/output/pretty_table_types.go — removed the AlignLeadingSymbol column option.
• pkg/output/pretty_table_table.go — removed the per-column alignment pass.
• pkg/output/pretty_table_layout.go — removed the alignLeadingSymbols/leadingSymbolWidth helpers and the now-unused unicode import.
• cmd/extension.go, cmd/tool.go — dropped AlignLeadingSymbol: true from the STATUS columns.
• pkg/output/pretty_table_responsive_test.go — removed the alignment-specific tests and option references.

Behavior

Before (plain values padded to align under symbol text):

STATUS
⟳ Update available
  Up to date
  Not installed

After (always left-aligned):

STATUS
⟳ Update available
Up to date
Not installed