feat: integrate bijou component library into CLI formatting layer

[flyingrobots]

Summary

Replace raw chalk + figures string concatenation in src/cli/format.js with the @flyingrobots/bijou component library for structured, themed terminal output.

Motivation

The current CLI formatting is functional but plain — hand-rolled string concatenation producing flat text output. The bijou package family provides boxes, tables, badges, alerts, progress bars, theming, and automatic graceful degradation (interactive → static → pipe → accessible).

Scope

File	Action	Purpose
src/cli/ui.js	CREATE	Bijou context init + custom theme + styled helpers
src/cli/format.js	REWRITE	Replace chalk/figures with bijou components
bin/git-mind.js	EDIT	Call initUI() at startup
test/format.test.js	CREATE	Unit tests for rewritten format functions

What stays the same

• All --json output (schema-validated contracts, untouched)
• All domain logic (src/*.js — zero changes)
• All existing tests pass
• Pipe mode works (bijou auto-detects and strips ANSI)
• NO_COLOR respected (bijou handles natively)

Components used

• alert() for success/error/info/warning messages
• headerBox() for section headers
• table() for count/diff tables
• progressBar() for progress view
• badge() for status indicators and tags
• styled() + custom theme for consistent color tokens
• separator() for dividers

[flyingrobots]

Closing as out of focus for the current product stage. A richer CLI presentation layer may still be nice later, but it does not currently move an active Hill and should not compete with repository-understanding work for attention.