feat: add Claude Code subscription provider (default for the kit)

KeiSeiKit installs into Claude Code, but the wizard offered no Claude under
`subscription` (only OpenAI Codex) — a Claude user picking subscription got no
Claude. Add provider `claude-code` (transport=subscription, endpoint=
local:claude-cli, auth_env=_, no API key) + 3 claude-code models (sonnet
default, opus, haiku), mirroring the codex subscription convention. Listed
before codex so it's the default pick under subscription.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

models.toml

@@ -58,6 +58,55 @@ verified_at = "2026-04-30"
 deprecated_at = ""
 notes = "Architecture, novel reasoning, math derivation. Tokenizer overhead 1.35x vs Sonnet."
 
+# ─── Claude Code (subscription) ──────────────────────────────────────────
+# Same Claude models, reached via the `claude` CLI under the user's plan.
+# Subscription billing → per-token cost 0 (mirrors the codex convention).
+
+[[model]]
+provider_ref = "claude-code"
+id = "claude-sonnet-4-6"
+slug = "sonnet"
+display_name = "Claude Sonnet 4.6 (Claude Code)"
+context_window = 1000000
+cost_input_per_mtok_micro = 0               # subscription, not per-token
+cost_output_per_mtok_micro = 0
+cache_write_5m_per_mtok_micro = 0
+cache_write_1h_per_mtok_micro = 0
+cache_read_per_mtok_micro = 0
+verified_at = "2026-05-22"
+deprecated_at = ""
+notes = "Default model. Balanced; RULE 0.20 default for code-implementer-* / researcher-*."
+
+[[model]]
+provider_ref = "claude-code"
+id = "claude-opus-4-7"
+slug = "opus"
+display_name = "Claude Opus 4.7 (Claude Code)"
+context_window = 1000000
+cost_input_per_mtok_micro = 0               # subscription, not per-token
+cost_output_per_mtok_micro = 0
+cache_write_5m_per_mtok_micro = 0
+cache_write_1h_per_mtok_micro = 0
+cache_read_per_mtok_micro = 0
+verified_at = "2026-05-22"
+deprecated_at = ""
+notes = "Architecture, novel reasoning, math derivation."
+
+[[model]]
+provider_ref = "claude-code"
+id = "claude-haiku-4-5-20251001"
+slug = "haiku"
+display_name = "Claude Haiku 4.5 (Claude Code)"
+context_window = 200000
+cost_input_per_mtok_micro = 0               # subscription, not per-token
+cost_output_per_mtok_micro = 0
+cache_write_5m_per_mtok_micro = 0
+cache_write_1h_per_mtok_micro = 0
+cache_read_per_mtok_micro = 0
+verified_at = "2026-05-22"
+deprecated_at = ""
+notes = "Cheapest Claude. Single-edit, formatting, lookup."
+
 # ─── OpenAI ────────────────────────────────────────────────────────────
 
 [[model]]

providers.toml

@@ -73,6 +73,19 @@ rate_limit_rpm = 0                 # per-deployment quota; see Azure portal
 billing_currency = "USD-azure"
 notes = "OpenAI через Azure — для enterprise с Azure-биллингом. Нужны resource+deployment."
 
+[[provider]]
+id = "claude-code"
+display_name = "Claude Code (subscription — your claude CLI, no API key)"
+transport = "subscription"
+endpoint = "local:claude-cli"      # invoked via the `claude` CLI (Claude Code), not HTTP
+auth_scheme = "oauth-subscription"
+auth_env = "_"                     # no env — Claude Code handles auth (claude.ai Max / Pro)
+retry_max = 1
+retry_backoff_ms = 0
+rate_limit_rpm = 60                # Claude subscription quota
+billing_currency = "USD-subscription"
+notes = "Default for the Claude-Code-native kit. Uses ambient `claude` CLI OAuth; no API key needed."
+
 [[provider]]
 id = "codex"
 display_name = "OpenAI Codex (ChatGPT OAuth)"