v0.26.2

Patch release: a compaction fix, a price correction, maintenance and a docs review; no API change. yoagent-rutis (0.10.0) and yoagent-workers (0.3.0) are unchanged.

• mistral_large_4 repriced to $0.70 / $2.10 per million tokens, cached $0.07 (was $1.36 / $4.18 / $0.14). Mistral's model page and models.dev both list the new rate, with no sale marking; the release price audit caught the drift. The pricing docs no longer describe Mistral's launch sale as running (it ended about 2026-10-20).
• Dependency floor: rand 0.10.1 (was 0.10.0), past RUSTSEC-2026-0097. yoagent only calls rand::random (retry jitter), so it was not affected; the floor keeps a fresh resolve off the unsound release.
• Docs: a full review of every page against the code (#398) — errors fixed (among them: prompt() during a run waits rather than panicking; DecisionError::Refused ends a fallback chain; the extensions spend bucket; a non-compiling OpenAiCompat example; Bedrock has no default base URL) and gaps filled (0.26.1's URL redaction in the MCP guide, ModelConfig::preset / generic, the extension builders in the API reference, the synchronous InputFilter); llms.txt lists every page.
• CI: every actions/* step on its current major, off the deprecated Node 20 runtime (#397).
• Compaction keeps the task prompt and the latest ask (#150). When the keep_first head and the keep_recent tail alone exceed the compaction target (a small budget, bulky tool results), level 3 kept only the newest messages that fit the target — dropping the task prompt first, and leaving only the [Context compacted] marker when the newest turn alone exceeded the target (#150's 22 msgs -> 1 msg). It now keeps, in order, the head, the latest user message a person wrote, the newest turn and as much of the rest of the tail as fits — overshooting the target, up to the budget, rather than cutting into them; past the budget the head goes first, then the ask, and the newest turn is cut last (a turn bigger than the budget leaves the marker and the ask). A cut past the latest user message on the normal path keeps it too, right after the marker. The kept head also never ends partway through a multi-call turn's results, which could leave a tool call unanswered, and the guaranteed tail is never less than the newest turn: with a small keep_recent the cut could drop the turn whose results the model was waiting on. In the offline sweep (docs/evals/compaction-defaults.md) task-prompt loss goes from 100% to 0% at a 26K budget, with no marker-only compactions; tool-heavy sessions compact ~14% more often there (they now keep more). At the default 96K the only change is that tool-heavy sessions no longer lose the latest ask (2% of compactions before).