feat(cli): move version to a subcommand and make -v verbosity

[jmgilman]

Summary

P1 / PR-1.2 of the CLI UX overhaul. Frees -v for verbosity and lands the global UX flag surface + verbose logging on slog.

⚠️ Breaking changes (pre-1.0, intentional — locked decisions #1 & #3)

• yacd --version is removed. Cobra's Version: field and the --version flag are dropped; use yacd version (prints the same build-metadata line to stdout).
• -v/--verbose is always verbosity (a count: -v, -vv, -vvv), never version.
• -q/--quiet forces the logger off (overriding -v/--log-level); data and the final returned error reason still print.

What's here

• Drop Version:/SetVersionTemplate; add version.go (yacd version → stdout).
• Add persistent flags --verbose -v (count), --quiet -q, --non-interactive, --color, --no-color. This PR consumes only -v and -q; --non-interactive/--color/--no-color are registered for the foundation and wired into ui.IO in PR-1.4 (adding their consumer — resolveUX — now would be dead code that fails the unused linter).
• PersistentPreRunE reads -v/-q directly off cmd.Flags() (flag-only, env-immune) without changing loadRuntimeConfig's signature (that change is coupled to deleting the 11 re-call sites and lands atomically in PR-1.4). It raises the resolved --log-level by the verbose count via raise() and forces the logger off under -q.
• raise(base, count): additive along error<warn<info<debug, capped at debug, never lowers; newLogger gains a quiet param returning slog.DiscardHandler.
• Added build BuildInfo to commandContext so version (and tests) read it symmetrically.

Note on raise() semantics

The 063 design prose is internally inconsistent: §6 describes additive warn→info→debug stepping, but one example claims YACD_LOG_LEVEL=warn … -v → debug. Additive-by-one is the only model that delivers goal 5's graduated -vvv control and matches the stepping description, so I implemented that: raise("warn",1)=="info", raise("info",1)=="debug". (Flagging for visibility; -v from the default info base still reaches debug as expected.)

Testing

• gofmt/go vet/go build clean; moon run root:check (golangci-lint + generated-drift) green; moon run root:test (full envtest gate) green; git diff --check clean.
• New/changed tests: version subcommand prints to stdout (byte-identical to the old --version); --version is now an unknown flag; version still prints under -q (data survives the mute); -vvv version is accepted (verbosity, not version); raise() table (env-base steps, cap, never-lowers, unknown/negative); newLogger discard-under-quiet + level gating.

Part of the P1 foundation series (1.1 #119 merged → 1.2 → … → 1.6).

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