[codex] Add collapsible kanban columns and compact cards

[artinflight]

What changed

This PR adds compact, collapsible kanban columns and denser kanban cards.

• adds per-column collapse/expand state on the kanban board
• persists collapsed column state per project/view in UI preferences
• renders collapsed columns as slim placeholders with a sticky vertical label and expand affordance
• makes card titles wrap fully instead of truncating
• hides card descriptions by default behind an inline expand/collapse toggle
• keeps desktop and mobile layouts distinct so mobile stacks statuses vertically while desktop keeps multi-column kanban behavior

Why

The board was taking up too much horizontal and vertical space in dense projects:

• wide columns made it harder to focus on the statuses that matter right now
• long card descriptions increased vertical sprawl
• truncated titles hid too much useful information

The new behavior lets users compress the board without losing access to full titles or hidden details.

User impact

Users can now:

• collapse low-priority statuses temporarily
• scan more cards per viewport because descriptions are hidden by default
• read full card titles without opening the issue
• use the kanban board on mobile with stacked status sections instead of squeezed side-by-side columns

Root cause

The existing board had fixed always-expanded status columns and card content that prioritized description preview over density. It also truncated titles aggressively, which reduced scanability on cards with longer names.

Validation

• pnpm run web-core:check
• pnpm run ui:check
• pnpm run local-web:check
• verified in a repo-backed test instance against the live backend before preparing this PR

[Juanlucasbg]

Rebase status (informational — draft respected)

Draft PR. Posting rebase data as a heads-up:

• Rebase against current main: clean (no conflicts).
• Mergeable on GitHub.

When you mark this ready-for-review, the standard merge gate applies — no rebase work needed first.

— Automated rebase status check; no action requested while in draft.