charm stack v1→v2 migration: glamour + lipgloss + bubbletea + bubbles

[schmitthub]

Sub-issue of #402 (dependency currency sweep).

Current vs available (verified via module proxy)

module	ours (v1 gen)	current v2
glamour	github.com/charmbracelet/glamour v1.0.0	charm.land/glamour/v2 v2.0.1
lipgloss	github.com/charmbracelet/lipgloss v1.1.1-0.2025... (untagged pseudo-version)	charm.land/lipgloss/v2 v2.0.4
bubbletea	github.com/charmbracelet/bubbletea v1.3.10	bubbletea v2
bubbles	github.com/charmbracelet/bubbles v1.0.0	bubbles v2

All four are coherently on the v1 generation today (which is the correct current state — mixing generations is the smell). The pseudo-version lipgloss pin is pulled in by glamour@v1.0.0 requiring an untagged lipgloss commit.

Motivation

• Changelog-notification wrap regression observed under glamour v1.0.0 (WithWordWrap(0)); glamour v2's headline is improved text wrapping (CJK/emoji) — may fix it natively.
• Modern lipgloss v2 color model; drops the untagged pseudo-version for clean tags.
• Removes muesli/termenv direct usage (v2 uses lipgloss for color downsampling).

Why it must be coordinated (not piecemeal)

lipgloss v2 is built for bubbletea v2 / bubbles v2; glamour v2 requires lipgloss v2. Bumping glamour alone forces lipgloss v2 → version skew with bubbletea/bubbles v1. Migrate the four together or not at all.

Blast radius

• Import-path rewrites to charm.land/.../v2 (+ /ansi, /styles).
• iostreams color handling: WithColorProfile removed → downsample via lipgloss.Print; delete markdownColorProfile(); WithStyles(ansi.StyleConfig) survives (new path).
• lipgloss direct consumers: internal/iostreams/{styles,layout,table,colorscheme}.go (one package, contained by the "only iostreams imports lipgloss" rule).
• TUI layer: internal/tui (bubbletea v1 components) — monitor up, image build display, all live-interactive views.
• Golden regen: markdown_test, changelog_preview_test, any TUI goldens.

API breaks to handle

• glamour: WithAutoStyle + WithColorProfile removed; new module path.
• lipgloss v2: color types, renderer removal, adaptive-color API changes.

Effort

A whole-TUI-layer initiative, not a chore.

Interim

The glamour-v1 wrap regression is fixed separately on v1 — do not block that on this migration.