feat(cli): width-aware item-list table (TASK-2030)

[xarmian]

Summary

Rewrites PrintItemTable in internal/cli/format.go to be terminal-width-aware and ANSI-safe. Refs TASK-2030 (PLAN-1985).

The old renderer used text/tabwriter, which counts ANSI color escape bytes as visible width — so on a TTY (where fatih/color emits codes) the header misaligned by ~12 columns. It also had no terminal-width awareness (long titles blew out the layout) and surfaced a useless BY (modifier) column while omitting STATUS/PRIORITY.

Changes

• Manual, ANSI-safe rendering replaces tabwriter for this function. All width math goes through a new displayWidth(s) helper that strips SGR escapes (\x1b[…m, compiled once as a package var) and counts runes.
• Terminal-width aware: probes term.GetSize(os.Stdout.Fd()), falling back to 120 columns when piped/non-TTY. Only the title is truncated (with …); the ref is never truncated.
• New columns / layout (DR-1): REF/TITLE · STATUS · PRIORITY · COLLECTION · UPDATED. Drops the BY column. STATUS/PRIORITY are parsed from the item's fields JSON and rendered via the existing ColorizedStatus / PriorityColor helpers (dim — when absent).
• Testability refactor: PrintItemTable now just probes width and delegates to an unexported renderItemTable(w io.Writer, items, maxWidth) core, tested against a bytes.Buffer with a fixed width.
• Exported signature func PrintItemTable(items []models.Item) is unchanged; callers (cmd_item.go) are untouched.

Notes / decisions

• Per-rune width is approximated as 1 column (emoji/CJK double-width is a documented, pre-existing limitation) — no new dependency, per task spec.
• Narrow-terminal overflow (below ~44 cols) is the specified "degrade gracefully" behavior: ref + short columns are never truncated; titleBudget is floored at 0 and the flexible header obeys the same budget as data rows.
• Titles carrying raw SGR escapes are stripped before measuring/truncating, so a title can never be sliced mid-escape and the width budget stays exact.

Gates

• go build ./... — PASS
• go vet ./... — PASS
• make lint (golangci-lint) — PASS (0 issues)
• go test ./internal/cli/... ./cmd/pad/... — PASS

Codex review

Verdict: CLEAN (4 rounds). Caught and fixed: header-not-fitting-budget in the degraded narrow regime, and mid-escape title slicing for titles containing embedded ANSI. The two originally-flagged scope items (rune-width approximation; narrow-terminal overflow) are explicitly accepted per the task/DR-1.