v0.6.0 — agent core: cost-aware sub-agents, budgets, recovery, persistence

The largest release since the TypeScript harness shipped: the coding agent gains sub-agent orchestration, budget following, failure recovery, and a durable local record — every piece wired into Minima's cost-aware routing — plus server-side routing fixes.

CLI / coding agent

• task tool — sub-agent delegation: the agent can decompose work into subtasks, each cost-routed to its own model via Minima, run in parallel (bounded) with depends_on ordering, per-node budgets, timeouts, and abort propagation.
• Budgets: --budget <usd> (graduated warnings at 50/75/90/100%) and --budget-enforce (refuses runs before any provider spend once exhausted). /budget command + status-bar segment. Cross-session-safe atomic reserve/reconcile.
• Recovery ladder: a provider failure or judged-below-threshold turn automatically retries on the server's next-ranked model (failed model excluded, per-rung feedback, max 3 attempts).
• --slider N: the cost/quality dial (0 = cheapest acceptable, 10 = quality-first) from the command line.
• Persistent runs: every conversation, tool call, and routing decision lands in a local SQLite record — /resume restores context and the cost ledger, /name persists, /cost shows quality-per-dollar, savings vs all-premium, and optimal-cost-ratio.
• Feedback truth: run-total cost reporting, no fabricated verification flags, unjudged turns tagged — the learning loop only gets honest signal. Optional LLM judge (MINIMA_LLM_JUDGE=1) with transient-failure retry.
• Effort routing (preview, MINIMA_AUTO_EFFORT=1): server-classified difficulty picks each prompt's thinking level.

Routing service

• Classifier overhaul: feature-vector classification (per-rule profiles, uncertainty, neighbor blending — thanks @404-ammar-not-found, #41/#46) with strongest-signal task-type selection and coding-agent vocabulary — real coding prompts no longer misprice as one-line summaries (benchmark: 73% vs 70% on the labeled set, both live misroutes fixed).
• Savings accounting resilience: decision-log reconciliation now happens before the memory write, so /v1/savings realized figures survive a memory-backend outage.

Docs

• docs/agent-core-architecture.md + docs/agent-core-implementation-plan.md — the full design + roadmap behind this release.

Homebrew: brew upgrade minima. PyPI SDK unchanged.